Posts Tagged ‘PCBA’

What file type is used for PCB schematic drawings?

Tuesday, September 3rd, 2024

PCB printed circuit boards are essential to achieving the functionality of electrical devices, but before the final board can be manufactured, a carefully drawn schematic is essential. The PCB schematic is the blueprint that guides the actual design and manufacture of the circuit board. The schematic and Gerber files are key elements in the PCB manufacturing process, and each plays a different role.

What is the schematic file for PCB?

The schematic file is the foundation of any PCB design. It represents the logical connections and relationships between different components in the circuit. Think of it as a map showing how each component, such as resistors, capacitors, and microcontrollers, is connected to form a functional circuit.

What file type is used for PCB schematic drawings?

When creating a PCB, the schematic file is the first step. It is used to document the design and is essential to ensure that the final product functions as expected. Engineers use specialized software to create these schematic files, which can then be converted into the layout of the physical PCB.

What is PCB CAD file?

‌PCB CAD files‌ are files directly output or saved by EDA software for PCB design. These files contain information about each layer of the PCB, network connection information, component information, etc. They are very comprehensive and contain almost all the information of the circuit board.

This format is mainly used for the storage and exchange of circuit board design, and contains information such as the layout, connection, pad, and drilling of each component on the circuit board.

In circuit board design, designers use circuit board design software to draw circuit schematics, layout, connection, component placement, etc., and finally generate a PCB file, and then load the file onto the circuit board to realize the production of the circuit board.

In addition, PCB CAD files play an important role in the offline programming of SMT placement machines. Offline programming refers to the work of compiling SMT placement programs on a computer using offline programming software and PCB CAD design files.

This programming method can save online programming time, thereby reducing the downtime of the entire PCBA processing and improving the utilization of equipment. Offline programming software is often used in automated production processes to ensure efficient and accurate completion of the placement of electronic components.

What files are needed to make a PCB?

Creating a PCB is a multi-step process involving multiple different files, each with its own unique purpose.

1. Schematic file (.sch, .dsn): represents the logical connection of the circuit and is the blueprint of the entire PCB design process.

2. Netlist file (.net, .xml): generated based on the schematic, lists all components and their connections.

3. Gerber file (.gbr, .pho): Gerber file is the most important file for manufacturing PCB. Define each layer of the PCB, including copper wire, solder mask and silk screen printing layer, each layer of the PCB requires its own Gerber file.

4. Drill file (.drill, .drl): specifies the location of the holes drilled on the PCB. It includes information on the size and location of each hole.

5. Bill of Materials (BOM, .bom, .csv): BOM lists all the components required to assemble the PCB. Including part number, quantity and other details required for procurement.

6. Pick and place file (.txt, .csv): used in the assembly process to specify the precise location of each component on the circuit board.

What is the file type for circuit schematic?

The file type for a circuit schematic can vary depending on the software used to create it.

1. .SCH: This is the most common file extension for schematic files.

2. .DSN: This is another standard for schematic files.

3. .PDF: Although PDF is not a design file, it is often used to share schematics for review. It provides a non-editable version of the schematic that can be easily viewed.

4. .XML: Some tools export schematics as XML files for compatibility with other software. This format is useful for exchanging data between different design tools.

5. .PNG/.JPG: Image formats such as PNG or JPG are sometimes used to share simple schematics. These are not editable, but can provide a quick way to visualize the circuit.

What does a Gerber file contain?

Gerber is actually a description file that focuses more on PCB manufacturing and production. It should be said that it was originally designed for plotters. Therefore, the content of Gerber basically includes the information required for PCB manufacturing, such as copper foil circuit layer, solder mask layer, silk screen layer, legend layer, drill layer, etc. Even solder paste printing layer, image recognition layer, annotations and production notes can be included in it in layers.

Advantages and Disadvantages of Gerber Files

Gerber files are not suitable for being used as a storage file format for current PCB design. Because the Gerber file format does not contain the connection information between the various circuit layers of the PCB.

If you look closely at the Gerber file structure, you will find that each layer is a small file, which means that the layers of Gerber are independent and unrelated to each other. They are like independent drawings. This feature had little impact on wiring engineers when PCBs were only single-sided or double-sided in the early days, but it is very disadvantageous in design, operation, debugging and verification for the increasingly complex multi-layer PCBs. Therefore, almost no one uses Gerber files as the file format for PCB design.

Because the amount of information in Gerber files is small, its file size is much smaller than other design files drawn by EDA or CAD software. In addition, its format is more irreversible in design and protects the original design. In addition, its vector image layered format is still very suitable for use in PCB manufacturing. Today, PCB production generally follows this layer to divide the process into different stages for production, so Gerber files are still widely used in PCB production.

Therefore, some design companies with high confidentiality requirements will convert the design files into Gerber before sending them to the PCB factory for production, trying to keep confidentiality.

Conclusion:

For anyone working in the electronics industry, it is essential to understand the various file types used in PCB design. From the initial schematic file to the final Gerber file, every step in the design process relies on accurate and compatible files. BEST Technology has a professional PCB design team with rich experience in different PCB designs. We can solve all your PCB design problems.

What is led light circuit board?

LED light circuit board is the abbreviation of printed circuit board, which is mainly used to carry and connect electronic components of LED lamps. ‌LED light circuit board is usually made of aluminum substrate and FR-4 fiberglass circuit board, where the LED aluminum substrate is printed on the aluminum plane with good thermal conductivity, and then the electronic components are soldered on it. ‌This design helps to improve the heat dissipation performance and stability of LED lamps, and ensure that the LED lamps can work stably for a long time.

What is an LED circuit board? How to make it?

The main function of LED light circuit board is to provide power to LED lamp beads and control the brightness and color of its LED lamp beads. In order to light up the LED lamp beads, an LED driving circuit is required, which includes constant voltage driving, constant current driving, PWM driving and other methods, which are usually integrated on the small circuit board of the LED lamp.

In addition, the design and manufacture of the LED lamp circuit board take into account the characteristics of LED, such as long life, high light efficiency, no radiation and low power consumption. Compared with traditional light sources, such as incandescent lamps and fluorescent lamps, LED lamps have significant advantages in efficiency, life and environmental protection.

How to make led light circuit board?

The process of making LED lamp circuit boards involves multiple steps, including welding, self-inspection, mutual inspection, cleaning, friction, wiring, etc.

Determine the direction of the lamp: the front side is facing up, and the side with the black rectangle is the negative end.

Determine the direction of the circuit board: the front side is facing up, and the end with two internal and external wiring ports is the upper left corner.

Welding: Carefully weld each solder joint to ensure fullness, cleanness, and no false soldering or leaking. ‌

Self-inspection: After completing the welding, first check whether there is a cold solder joint, leaking solder joint, etc. Use a multimeter to touch the positive and negative terminals of the circuit board to check whether the LED lights are on at the same time. ‌

Mutual inspection: After the self-inspection, it will be handed over to the person in charge for inspection. Only with the consent of the person in charge can it flow into the next process. ‌

Cleaning: Use 95% alcohol to scrub the circuit board to remove residues and keep the circuit board clean.

Friction: Use fine sandpaper (coarse sandpaper if necessary) to grind off the burrs on the edge of the circuit board so that the circuit board can be placed flatly in the fixing seat. ‌

Wiring: Use blue and black thin wires to connect the circuit board. The wiring point close to the inner circle is negative and connected to the black wire; the wiring point close to the outer circle is positive and connected to the red wire. ‌ Make sure the wires are connected from the back to the front. ‌

Self-check and mutual check: Check the wiring to ensure that each wire passes through the pad, the length of the wires on both sides of the pad that remain on the surface should be as short as possible, and the thin wires will not break or loosen when gently pulled. ‌‌

Through the above operations, the production of the LED lamp circuit board can be completed. ‌Each step is crucial, especially the welding and wiring parts. It is necessary to ensure the quality of the welding points and the correct connection of the wires to ensure the normal operation of the circuit board and the normal lighting of the LED lamp.

Why do you need a resistor with an LED?

When using LED, a resistor needs to be connected in series to control the current, prevent excessive current from damaging the LED, and ensure that the LED can emit light normally. ‌

LED is a semiconductor device that can directly convert electrical energy into light energy. Due to its special material properties, LED is very sensitive to current, and excessive or insufficient current may cause the LED to malfunction or be damaged.

Therefore, when the LED is connected to the power supply, a resistor is needed to limit the current to ensure that the LED can work stably and safely.

The main function of this resistor is voltage division and current limiting. It is used to adjust the current passing through the LED to prevent the LED from burning out due to excessive current, while also ensuring that the LED can emit light of appropriate brightness.

Specifically, when current passes through the LED, the resistor will produce a certain voltage drop, thereby reducing the voltage applied to both ends of the LED, thereby controlling the current passing through the LED.

What resistor to use with LED?

Use an LED resistor calculator to help determine the required resistor value. ‌

When using LEDs, in order to protect the LED and ensure its normal operation, it is usually necessary to limit the current by connecting an appropriate resistor in series. This is because each LED has a maximum current value, exceeding which may cause the LED to be damaged.

Using an LED resistor calculator can help you determine the required resistor value to ensure that the current does not exceed the maximum tolerance of the LED.

By entering the relevant parameters of the LED (such as the rated current and voltage), the calculator will automatically calculate the required resistor value to protect the LED from overcurrent damage.

This method is a common practice and is applicable to any situation where a number of LEDs are used in series. In this way, the safe operation of the LED can be ensured while avoiding damage caused by excessive current.‌

How to improve the heat dissipation performance of LED light circuit boards?

The key to improving the heat dissipation performance of LED light circuit boards is to optimize the heat dissipation path, use efficient heat dissipation materials, and adopt advanced heat dissipation technology.

Optimize the heat dissipation path:

Understanding the heat transfer path of the heat generated by LED components is the first step to improve heat dissipation performance. Heat moves from the LED components through the package wires to the circuit board, and then dissipates through the heat sink.

The heat dissipation efficiency can be effectively improved by using materials with good thermal conductivity, expanding the cross-sectional area of the path (such as using thick copper wire), and applying thermal lubricants to reduce the gaps in the connection parts.

Use efficient heat dissipation materials:

Metals such as copper and aluminum are often used to make heat sinks because of their good thermal conductivity. In addition, new materials such as graphene are also used to make heat sinks because of their excellent thermal conductivity. These materials can significantly improve heat dissipation efficiency. ‌

Adopting advanced heat dissipation technology:

Micro-groove group composite phase change integrated cooling technology is an advanced heat dissipation technology. It effectively removes the heat of high-power electronic devices by changing the closed-circulation cooling medium into a nano-scale water film and utilizing its strong evaporation ability and latent heat exchange ability.

As an excellent thermal conductive medium, thermal conductive silicone grease has excellent electrical insulation and thermal conductivity. It can penetrate into the tiny depressions on the metal surface, increase the contact area, and improve the efficiency of heat conduction from the LED chip to the aluminum substrate.

Are LED PCBs only used in lighting systems?

The application range of LED PCB (printed circuit board) is far more than lighting systems. In addition to lighting systems, LED PCB is also widely used in other fields. For example, LED lamps are one of the most common products using LED PCBs. Whether it is home lighting, commercial lighting or outdoor lighting, LED lamps occupy a large market share.

Compared with traditional incandescent lamps and energy-saving lamps, LED lamps have higher luminous efficiency, longer service life and lower energy consumption. They also have features such as dimming and color change, which can meet the needs of different scenarios. ‌

In addition, LED PCB is also used in LED display screens, LED backlight sources and automotive lighting. LED display screens provide high-definition and high-brightness display effects in large-scale events such as sports events, concerts, and exhibitions, bringing a shocking visual experience to the audience.

LED backlight sources have become the mainstream choice in electronic products such as LCD monitors, mobile phones, and tablet computers. Compared with traditional cold cathode fluorescent lamps, LED backlight sources have higher brightness, longer service life and lower energy consumption. At the same time, they can achieve local dimming, improve display effects and reduce energy consumption.‌

In the field of automotive lighting, with the advancement of automotive lighting technology, more and more cars are beginning to use LED lamps. Compared with traditional halogen and xenon lamps, LED car lights have higher brightness, longer service life, lower energy consumption, faster response speed and better heat dissipation performance, which improves driving safety. ‌

From this we can know that the application of LED PCB is not limited to lighting systems, but is widely used in many fields, including but not limited to lighting, display technology, backlight sources of electronic products, and automotive lighting. ‌

Conclusion:

Designing PCB for LED lights is a complex but critical task that requires careful consideration of various influencing factors, from the selection of manufacturing materials to the testing of thermal conductivity and the quality testing of finished products. Choosing Best Technology has expert design assistance and reliable manufacturing processes, which will allow you to obtain the best results for LED light PCB design. ‌

What is the average cost of a PCB?

The average cost of PCB varies due to many factors, and there is no fixed value. ‌

The cost of PCB is mainly composed of the following parts:

1. Substrate cost: Substrate is the basic component of PCB. Common material types include FR4, CEM-1, aluminum substrate, etc. The price of different types of substrates varies greatly.

How much does a custom PCB cost per unit? How to calculate?

2. Process cost: The manufacturing process of PCB includes inner layer circuit production, lamination, drilling, electroplating, outer layer circuit production, solder mask treatment, text printing and surface treatment. Each step requires professional equipment and technicians to operate, so there will be corresponding costs.

3. Inspection cost: After the PCB is manufactured, a series of tests are required to ensure its quality, including electrical performance testing, reliability testing, and appearance inspection.

4. Other additional expenses: In addition to the above main costs, there are some additional expenses to consider, such as special design or modification services may require additional design fees. In addition, additional costs such as packaging, transportation, and taxes also need to be taken into consideration.

In summary, the cost of PCB is composed of multiple aspects, including substrate cost, process cost, inspection cost, and other additional expenses, which need to be comprehensively evaluated based on specific board type, number of layers, drilling amount, surface treatment process, and other factors.

How to calculate PCB design cost?

‌Material cost is an important part of design cost, including board, solder mask ink, chemical agents, etc. These costs are relatively easy to calculate, but the additional losses caused by material loss and risks during storage and use need to be considered.

‌Process cost covers equipment use time, worker wages, energy consumption, etc. When calculating the cost of equipment use, the frequency and duration of equipment use and the total investment cost should be taken into account.

‌Equipment depreciation and maintenance costs‌ are also a part that cannot be ignored, including the original price of the equipment, accumulated depreciation, and maintenance and repair costs.

‌Other related costs‌ such as administrative costs, quality control costs, and R&D costs, although more difficult to calculate, have a significant impact on the total cost of the project.

Material costs include substrate materials, circuit board materials, and copper foil, processing costs involve drilling, copper plating, graphic etching and other processes, and labor costs include direct and indirect labor costs. Through these calculations, plus a reasonable profit margin, the final PCB quotation is obtained.

What is the most expensive PCB?

The most expensive PCB may be an electroless nickel electroless palladium immersion gold (ENEPIG) PCB.

This electroplating material has a copper-nickel-palladium-gold layer structure that can be directly bonded to the electroplating layer through wires. The last layer of gold is very thin, just like electroless nickel immersion gold (ENIG).

The gold layer is soft, so excessive mechanical damage or deep scratches may expose the palladium layer. Although the gold layer is soft, ENEPIG’s PCB is often considered the first choice in high-end applications due to its high-quality electrical performance and durability, so its cost is relatively high.

In addition, the production of high-end precision PCB circuit boards is also expensive, including multi-layer boards, boards with BGA, HDI circuit boards, etc. These products usually require more complex production processes and higher material quality, so the cost is also relatively high.

How much does PCB assembly cost per component?

The PCB assembly cost of each component is composed of multiple factors, including board costs, processing costs, testing costs, and other additional costs. ‌

Board costs are an important part of PCB assembly costs. The types of boards, such as FR4, CEM-1, aluminum substrates, etc., have large price differences.

FR4 boards are widely used due to their excellent electrical and processing properties, but their prices are affected by fluctuations in the prices of raw materials such as international copper prices, epoxy resins, and glass fiber cloth.

Aluminum substrates are favored in certain specific applications due to their good heat dissipation performance, but their prices are usually much higher than FR4 boards.

‌Processing costs‌ cover multiple links in the PCB manufacturing process, such as inner layer circuit production, lamination, drilling, electroplating, outer layer circuit production, solder mask, text printing and surface treatment.

Each link requires professional equipment and technicians to operate, so there will be corresponding costs. In particular, the costs of steps such as drilling and electroplating will vary according to factors such as the number of holes, the area and thickness of the electroplating.

‌Testing costs‌ are an important link to ensure the quality of PCBs. After the production is completed, the PCB needs to undergo a series of tests, including electrical testing, reliability testing, and appearance inspection.

These tests require not only professional testing equipment, but also experienced testers to operate and analyze the results, so certain costs will also be incurred.

‌Other additional costs‌ include additional design fees that PCB manufacturers may charge if customers require special design or modification services. In addition, there are some additional costs such as packaging, transportation and taxes that need to be taken into account.

In summary, the PCB assembly cost of each component is determined by the board cost, processing cost, testing cost and other additional costs, and the specific cost will vary according to the specific needs of the project and the manufacturer’s quotation.

What is the cheapest PCB finish?

The cheapest PCB surface treatment process is hot air solder leveling (HASL). ‌

HASL is a commonly used PCB surface treatment process, which is divided into lead-containing tin and lead-free tin. It is one of the most commonly used and relatively inexpensive surface treatment processes.

This process is to immerse the circuit board in molten solder (tin/lead), and then the solder covers all exposed copper surfaces on the board to form a HASL surface finish.

HASL is not only one of the cheapest types of PCB surface treatment, but its process temperature is 250℃, the shelf life can reach 12 months, and the surface treatment thickness ranges from 1-40um, making it an economical and practical choice.

In addition, HASL is divided into leaded and lead-free. Although the leaded version is gradually replaced by the lead-free version for environmental reasons, the lead-free HASL still maintains a low cost, making it the preferred choice for projects with limited budgets‌.‌

Do vias make PCBs more expensive?

Vias may indeed increase the cost of PCBs. ‌

Vias are an important part of multi-layer PCB boards, and they play a key role in the design and manufacturing process of circuit boards. Vias can be divided into buried vias, blind vias and through holes. Among them, through holes pass through the entire circuit board and are used to achieve internal interconnection or component installation and positioning. They are the most commonly used types.

The number and type of vias directly affect the cost of the PCB, because each via needs to go through processes such as drilling and electroplating, which account for a considerable part of the cost of PCB board manufacturing.

Factors that affect the cost of PCBs also include the size of the vias. The smaller the via, the greater the manufacturing difficulty, and the corresponding increase in cost.

In addition, different types of vias require different processing technologies and materials, which also affects the cost. For example, the processing processes and difficulties of blind and buried vias are different, resulting in different prices.

The price difference between blind and buried vias is mainly caused by many factors such as material cost, complexity of processing process and difficulty of processing. Blind vias require double-sided or multi-layer composite boards, which have higher material costs, while buried vias can be processed using single-sided boards, which have relatively low costs.

In addition, the processing processes of blind vias are diverse, the process is complex, and higher technology and cost are required. The processing time is long and the manufacturing cost is relatively high.

In summary, the number, type, size and processing method of vias will affect the cost of PCB. When designing PCB, it is necessary to find a balance between function and cost to optimize the design and cost control.

Conclusion:

The unit cost of PCB is affected by many factors, including but not limited to the number of layers, material, drilling amount, and surface treatment process of the board. BEST Technology has many years of experience in PCB board design and has skilled experience in handling various factors that affect PCB cost. It can help you find the best way to solve all your concerns about PCB cost.

What files do I need to make a PCB?

Making PCBs (printed circuit boards) requires a series of files to ensure the smooth progress of the manufacturing process and the quality of the product.

‌Gerber file‌: This is the most common and crucial file in PCB manufacturing. It contains the geometric information of each layer of the PCB, such as copper lines, pads, solder mask layers and silk screen layers, and also includes separate files for each PCB layer, such as top copper, bottom copper, solder mask, silk screen layer, etc. ‌

What file types are used for PCB design?

‌Drill file‌: Provides drilling coordinates and size information for PCBs, and specifies the aperture size of components, vias and mounting holes. Drill files are usually generated in Excellon format or as separate ASCII files‌.

‌Bill of Materials (BOM): A BOM is a detailed list of all components used in a PCB design, including information such as part number, component value, description, and quantity, which helps ensure that all required components are correctly sourced and placed on the PCB.

‌Center Coordinate File: Also known as a pick and place file, it provides coordinate and orientation information for each component on the PCB and is essential for the automated assembly process. Center coordinate files are usually provided in CSV format.

‌Fabrication Drawing: This is an engineering drawing that includes key information about the PCB, such as board dimensions, drill hole dimensions, layer stackup, tolerances, surface finish, and other manufacturing-related details, which serves as a reference for PCB manufacturers during the production process.

‌Assembly Drawing: Provides additional information for the PCB assembly process, including component placement details, reference numbers, orientation, and any special instructions for assembly technicians.

In addition, depending on the specific design and production needs, other documents may also be required, such as circuit diagrams, special layer files, installation instructions and precautions, etc. ‌ The preparation and provision of these documents is a key step in ensuring a smooth PCB production process.

What are Gerber files? What information do they contain?

Gerber files are a series of ASCII vector format files that define PCB design specifications. They are generated using electronic design automation (EDA) or computer-aided design (CAD) tools and provide information such as board configuration parameters, aperture descriptions, XY coordinate locations, and drawing instructions.

Configuration details include the size and shape of the PCB to be manufactured. Each layer of the board information is recorded in a different file to define components such as copper traces, pads, vias, solder mask, silk screen, and logos. The Gerber file indicates the XY coordinate location of each geometric shape and uses instructions to draw these shapes on the physical board.

The basic components of the Gerber file include: board size, shape, top assembly, top silk screen, top solder mask, top paste, top copper, internal signals, inner layers, bottom copper, bottom paste, bottom solder mask, bottom silk screen, bottom assembly, and manufacturing information (providing stackup, drilling details, cutting, etc.).

Gerber files generated by computer-aided manufacturing (CAM) tools have user-selected extensions, usually using project naming such as “.TOP” for top layer, “.BOT” for bottom layer, and “.drl” for drill data.

How is a PCB designed?

PCB design is a complex process that involves multiple steps and considerations to ensure the functionality and reliability of the final product.

‌Schematic Design‌: First, you need to prepare a schematic and component library. The schematic is the blueprint of the circuit design, while the component library contains information about the various components used in the circuit.

‌Component Symbols and Packages‌: The symbol of the component is used to represent the component in the schematic, while the package defines the physical form of the component on the PCB. The component symbol is used in the schematic design stage, while the package is used in the PCB layout and routing stages.

How is a PCB designed?

‌PCB Layout‌: The layout stage involves placing electronic components on the PCB, and factors that need to be considered include the orientation, size, and relative position of the components.

‌Routing‌: After the layout is completed, the next step is the routing stage, which is to connect the various components according to the needs of the circuit.

‌DRC Check‌: Design rule checking (DRC) is performed during the design process to ensure that the design complies with predetermined electrical and physical rules. This includes checking for shorts, open circuits, and other possible design errors.

‌Solder mask and solder paste layer‌: The solder mask is used to prevent unnecessary soldering, while the solder paste layer is used to specify solder joints. The correct design of these layers is critical to ensuring the reliability and manufacturability of the circuit board.

‌Network and DRC Check‌: In the final stage of design, network checks are performed to ensure that all components are properly connected, while DRC checks are performed to verify that the design complies with all electrical and physical rules.

‌Through the above steps, designers are able to transform the circuit design in the schematic into an actual, manufacturable PCB. This process requires comprehensive consideration of multiple factors such as the functionality, reliability, and manufacturing cost of the circuit.

‌What is the schematic file for PCB?

‌PCB schematic files are the main files used for circuit design, analysis, and debugging. They mainly show the electrical connection relationship between electronic components, but do not reflect the actual physical location of these components on the PCB board. ‌

Schematic Diagram is the basis of circuit design. It uses symbols and lines to express the connection and working principle of the circuit in a concise and clear manner, and pays more attention to the functional expression of the circuit.

Schematic diagram does not involve the specific layout and wiring of electronic components on the PCB board, so it focuses on the logical representation of the circuit rather than the physical implementation. ‌

In contrast, PCB design files plan the precise location and wiring of electronic components on the PCB board in detail, taking into account the connectivity of the circuit, and also comprehensively considering factors such as signal integrity, power distribution, thermal design, and mechanical strength. ‌

These design files are the main files used to manufacture actual electronic devices, including PCB layout and PCB wiring. The layout determines the location of electronic components on the circuit board, while the wiring involves the electrical connection between components. ‌

In general, schematic files and PCB design files play different roles in the design and manufacturing process of electronic products. The former focuses on the expression of circuit logic and function, while the latter focuses on converting this logic into actual physical implementation, including the specific location and connection method of components. ‌

What is the difference between PCB design and schematic design?

The main difference between PCB design and schematic design lies in their purpose, content and application scenarios. ‌

‌Purpose and content‌:

Schematic design focuses on describing the logical relationship and electrical performance of the circuit, using graphic symbols to display power, components and connections, and can clearly show the logical relationship of the internal circuit of the electronic device. It is mainly used for circuit analysis and design, helping to understand the working principle of the equipment and perform fault diagnosis‌.

PCB design focuses on describing the actual physical size, position and wiring of components, and is the actual circuit board layout and wiring design based on the schematic diagram. It is mainly used to guide the manufacture and assembly of PCBs, reflecting the actual layout and wiring of electronic equipment‌.

‌Application scenarios‌:

Schematic design plays an important role in the process of R&D, debugging and maintenance, and is a key tool for understanding the working principle of the equipment and performing fault diagnosis‌.

PCB design files are an important basis for the actual PCB board manufacturing and subsequent assembly, debugging and other processes‌.

In short, schematic design is the basis of electronic product development. It provides information such as the logical relationship and electrical performance of the circuit, while PCB design is the key link to convert the schematic into an actual circuit board. It is necessary to design components layout and wiring according to the requirements of the schematic.

What is a PCB stencil file?

A PCB stencil file is a pre-designed file template used to quickly generate PCB design files containing specific information.

These template files usually contain basic information such as board size, board layer settings, grid settings, and title bar settings. Users can quickly generate new PCB design files based on these templates, thereby speeding up the design process.

By using these templates, designers can avoid designing these basic settings from scratch, saving time and energy, and focusing on more complex circuit design details.

Conclusion:

There are many types of PCB design files, among which Gerber files are the most important. The information they contain is the most and the most important. The final quality of the PCB circuit board depends on the first step of design. BEST Technology has very professional PCB designers who have many years of industry experience and can meet all your needs.

Usb connector types

Types of USB connectors: different types of connectors with different shapes and directions, USB connectors can be separated into different types:

Type-A port: This is the most common type of USB port, the shape is long and rectangular, and the support is heat-resistant. Computer equipment such as printing machine, keypad, mouse button, driving device, etc. Type-A interface has USB 2.0 and USB 3.0 in different editions, among which USB 3.0 has faster speed, color is usually blue, and USB 2.0 has slow speed, color is black.

Type-B contact: Type-B contact shape is round shape, demand-specific connection. For general use, external equipment such as audio equipment, viewing equipment, etc., such as a 3.5 inch movable screen, stamping machine, display device, etc.Type-B verbal usage scene is relatively small, so this is an unusual sight in daily life.

Usb connector types:Type-A port:Type-B contact

Type-C port: Type-C port is a new type of USB port that has emerged in recent years. Built-in USB 3.1, Type-C interface configuration, mainstream interface type, intelligent handheld computer, flat panel battery, notebook battery, etc. The biggest feature of the Type-C interface is its support and double-sided insertion, making it convenient and convenient to use.

Type-C interface support further improves the speed and power of the power, and provides more advanced usage experience. Previously, when I came here, I was confused as to how to get around the main machine.

Mini USB port Micro USB port

Mini USB port Micro USB port: There are many types of ports for transfer equipment, digital reading machine, digital image machine, metering equipment, etc. Mini USB port ratio Micro USB port size is small, also known as a USB port, Micro USB port is smaller, thinner, supports OTG function, and provides a number of additional power functions. The Micro USB port is convenient and easy to use, and has various types of portability.

What functions does USB have?

Power Delivery of USB Ports
Some USB cables can deliver power as well as transfer data, but most USB cables can do both. Power delivery of USB ports is mainly divided into three categories: fast charging, quick charging, and power only.
USB Data Transfer Speed
USBs come in various sizes and shapes. Also, USB types have multiple speed standards. It is important to know that some USB cables are designed for data transfer only, while some can only deliver power. However, some USB cables can serve both purposes at the same time. Therefore, it is necessary to verify the performance of the cable before purchasing it.
USB Video Transfer
The ability of USB ports to power devices and transfer data between devices is already impressive enough. However, you can decide to integrate USB-C to connect a monitor in place of a VGA cable or HDMI. In addition, USB-C also supports 4K video transmission.

What are the advantages of USB interface?

Standard uniformity. The most common ones are hard disks with IDE interfaces, mouse and keyboards with serial ports, and printers and scanners with parallel ports. However, with USB, all these application peripherals can be connected to personal computers using the same standard. At this time, there are USB hard disks, USB mice, USB printers, etc.
Easy to carry. Most USB devices are known for being “small, light, and thin”, which is very convenient for users to carry large amounts of data with them.
Hot-swappable. That is, when users use external devices, they do not need to shut down and restart the computer, but directly plug in the USB when the computer is working.
Multiple devices can be connected. USB often has multiple interfaces on personal computers, and several devices can be connected at the same time. If a USB HUB with four ports is connected, four USB devices can be connected, and so on. You can connect all the devices to a personal computer at the same time without any problems (up to 127 devices can be connected).

How Do USB Ports Work?

USB is an external bus standard used to regulate the connection and communication between computers and external devices. The USB interface has plug-and-play and hot-swap functions. The USB interface can connect 127 peripherals, such as mice and keyboards. USB was jointly launched by Intel and other companies in 1994 and has successfully replaced serial and parallel ports since 1996. It has become a must-have interface for computers and a large number of smart devices today. For most engineers, the main obstacles to developing USB2.0 interface products are: facing the complex USB2.0 protocol, writing USB device drivers by themselves, and being familiar with microcontroller programming.

Why USB Ports Are Replacing Serial Ports

USB has three major advantages. It is superior to serial ports in several aspects.

Speed
USB ports are able to transfer data at a much faster speed. They work ten times faster than regular parallel ports. Also, they are much faster than serial ports. On average, serial ports offer a data transfer rate of 150kbps. On the other hand, USB ports offer about 12 Mbps. The data transfer rate depends on the type of USB port. For example, USB 2.0 has a maximum data transfer rate of 480 Mbps.

Compatibility
USB ports have replaced serial ports in the past few years. Various industrial devices are equipped with serial ports. This replacement has brought problems. USB ports are generally compatible with most USB devices.

Durability
USB ports are more durable than serial ports. The tiny pins on a serial port can break or bend easily. Whereas USB ports are very sturdy.

Frequently Asked Questions

The USB interface cannot be used. It may be due to a problem with the system. You need to check whether the system service is disabled or reinstall the operating system.

‌BIOS setting problem‌. If USB is disabled in BIOS or CMOS, you need to restore it to the factory default settings.

‌USB driver is not installed or the driver is deleted‌. You need to install the USB universal driver.

‌The front USB cable is not connected properly‌. Try to insert the USB flash drive into the USB interface on the back of the chassis.

‌The USB interface voltage is insufficient. When the mobile hard disk is connected to the front USB interface, it may not be recognized due to insufficient voltage. You should use a hard disk box with an external power supply or replace the power supply.

‌Compatibility issues between the motherboard and the system‌. For example, the compatibility issues between the NF2 motherboard and USB require the installation of the latest dedicated USB2.0 driver and patch.

‌System or BIOS problem‌. When USB is disabled in the BIOS or operating system, you need to enable options related to USB devices.

‌Be careful when plugging and unplugging. Do not unplug during reading and writing, otherwise the chip may be burned.

‌If the USB device is frequently disconnected‌, it may be that the USB cable connection is unstable or there is a problem with the USB port. Try changing the cable or connecting to another USB port.

‌If the USB device cannot be recognized or charged‌, make sure the device is compatible and the cable is intact. Try connecting to another computer or updating the driver.

What are the advantages of PCB?

‌Miniaturization and lightweight‌: As consumer electronics products increasingly pursue portability and compact design, thin PCBs have become a key factor in achieving device miniaturization, which can significantly reduce the thickness and weight of the device, making the product more in line with modern aesthetics and use. Habit.

‌Improved heat dissipation performance‌: Thin PCB has a smaller heat capacity, which helps to quickly dissipate the heat generated by electronic components, thus improving the overall heat dissipation efficiency of the device‌.

‌Reduced production costs‌: Thin PCBs require relatively less raw materials during the manufacturing process, and coupled with the possible reduction in the number of assembly layers, the material cost per unit area is reduced.

‌Adapt to high-speed signal transmission‌: Due to its low dielectric loss, thin PCB can effectively reduce signal transmission delay, improve signal integrity, and meet the needs of high-speed data transmission‌.

What are the advantages and disadvantages of PCB board?

‌High-density integration capability‌: PCB multi-layer boards allow for higher-density circuit layouts in a limited space. By arranging conductive paths and components between multiple layers, the size of the circuit board can be greatly reduced and electronic equipment can be improved. overall performance‌.

What are the disadvantages of PCB?

‌Mechanical strength problem‌: The mechanical properties of thin PCB are relatively weak, and it is easy to deform or break due to improper stress during assembly, transportation and even daily use‌.

‌Increased processing difficulty‌: Thin PCBs place higher requirements on the production process. Processes such as drilling, etching, and lamination need to be precisely controlled to prevent problems such as warping and breakage of thin plates‌.

‌Electromagnetic compatibility challenges‌: Thin PCB may increase parasitic capacitance and inductance, affecting the electromagnetic compatibility of the circuit‌.

‌Higher manufacturing costs‌: The manufacturing process of multi-layer boards involves complex processes such as multiple laminations, drilling, and electroplating, resulting in relatively high production costs.

Long production cycle: Due to the complex production process of multi-layer boards, the production cycle is usually longer than that of single-layer or double-layer boards, which may affect the product’s time to market and market competitiveness.

As an indispensable basic material in electronic manufacturing, PCB has the advantages of high reliability, high precision, and small size, but it also has disadvantages such as design and cost restrictions. When choosing to use PCB, you need to comprehensively consider its advantages and disadvantages as well as specific application scenarios.

What are the limitations of PCB?

The limitations of PCB (Printed Circuit Board) mainly include the difficulty of design and manufacturing, complex testing and troubleshooting, and environmental impact. ‌

‌Design and manufacturing are difficult‌: Designing multi-layer PCBs requires highly specialized knowledge and software tools to ensure signal integrity and optimization of power distribution.

‌Complex testing and troubleshooting‌: Due to the complexity of the multi-layer structure, once a failure occurs, it becomes more difficult and time-consuming to locate and repair the problem.

‌Environmental impact‌: Special chemicals and precious metals may be used in the production process of high-end multi-layer PCBs. If not handled properly, they may have a certain impact on the environment.

These limitations have put forward higher requirements for the design, manufacturing, testing and use environment of PCB, which require comprehensive consideration and optimization in terms of technology, cost, environmental protection and other aspects.

Why do PCB boards fail?

1. ‌Improper design‌

Including unreasonable PCB board design, improper part orientation design, automatic plug-in bent legs, etc. These problems may lead to short circuit faults, and the part orientation or design needs to be modified to avoid short circuits.

2. ‌Poor manufacturing‌

Problems during the manufacturing process, such as solder joint problems, damaged pads, improper installation of components, etc. These problems will affect the reliability of the welding and cause the circuit board to deform or crack.

3. Poor usage environment

PCB boards are affected by the environment, such as extreme temperature changes, excessive humidity, high-intensity vibration, etc., which may cause damage to the PCB board and affect its performance and reliability.

4. ‌Other reasons

It also includes circuit board aging, design defects, manufacturing process problems, etc., such as metal components on the circuit board reacting with oxygen, causing oxidation, or assembly deviations during the manufacturing process causing component position deviation, etc.

What can damage a PCB?

Factors that damage PCB (Printed Circuit Board) mainly include physical damage, chemical corrosion, electrochemical corrosion, electrostatic discharge, humidity and moisture, temperature changes, etc. ‌

1. ‌Physical damage‌: including vibration, falling, hitting, and stacking, which may cause PCB deformation and cracks, leading to circuit breakage or short circuit‌.

2. Chemical corrosion: The PCB surface may be exposed to chemicals, such as acids, alkalis or other corrosive solutions, causing corrosion.

3. ‌Electrochemical corrosion‌: When there is a potential difference between different metal components, a battery is formed in a humid environment, which accelerates the corrosion of one of the metals. This is called electrochemical corrosion‌.

4. ‌Electrostatic discharge‌: Electrostatic discharge is the invisible killer of PCB. It can generate thousands of volts in an instant, which is enough to damage the components on the PCB‌.

5. Humidity and moisture: Extreme temperatures or temperature changes, as well as moisture in the air, can cause PCB board damage, such as deformation, short circuit, corrosion and other problems.

6. ‌Temperature changes‌: Temperature changes can also cause solder joints, substrate materials and even casings to crack. If the circuit is going to be exposed to high temperatures, you may need to choose components that can withstand higher temperatures‌.

What is the lifespan of a PCB?

There is no fixed international standard for the service life of PCB, and its specific life span depends on many factors. ‌

‌Materials and manufacturing processes‌: The materials and manufacturing processes of the PCB board have a decisive impact on its service life. PCB boards made of different materials and processes have different service lives.

‌Normal use and maintenance‌: Under normal use and no damage, the life of the circuit board itself is quite long. Manufacturers usually give a lifespan indicator of about 5 years, but this does not mean that the circuit board cannot be used after 5 years. In fact, as long as a circuit board is properly maintained and maintained, it can last for decades‌.

‌Lifetime under specific conditions‌: For PCBs containing OSP parts, the vacuum seal is valid for up to 3 months. For non-OSP PCBs, if the storage period exceeds 6 months but is less than one year, the chip factory will bake them before producing them; if the storage period exceeds one year, they will be scrapped. Boards opened during production should be used within 24 hours.

The service life of PCB is not a fixed value, but depends on the specific situation. With proper design, manufacturing, use and maintenance, the life of a PCB can be significantly extended‌.

What are the dangers of PCB?

The wastewater generated during the PCB manufacturing process contains heavy metals (such as copper, nickel, lead, etc.) and organic matter. If these pollutants are discharged without proper treatment, they will cause serious pollution to the environment.

In electronic products, common defects in PCB boards include open circuits, short circuits, false soldering, solder beads, and substrate warping. These defects can cause electronic products to fail to work properly or even fail completely.

PCB circuit boards play a vital role in the manufacture of modern electronic devices. They are widely adopted for their high reliability, compactness, and high scalability. When choosing to use PCB circuit boards, you need to consider their advantages and disadvantages and make a wise decision based on the needs of the specific project.

BEST Technology has been deeply involved in the circuit board industry for many years and has many solutions for various PCB problems. You can find us for all your PCB problems.

What is the composition of solder paste?

Solder paste is a complex mixture of multiple components, and its main components include metal powder, flux and solvent.

What is solder paste? What is its function?

The metal powder in solder paste is usually composed of metal alloys such as tin, silver and copper. The particle size and distribution of metal powder have a direct impact on the welding effect. The smaller the particle size, the more uniform the distribution, and the better the welding effect.

At the same time, the composition of the metal alloy also determines the mechanical strength and electrical properties of the solder joint.

Flux is another important component in solder paste. Its main function is to remove oxides on the welding surface and improve the wettability and reliability of welding.

The type and formula of flux directly affect the melting state and solder joint quality during the welding process. Common fluxes include rosin-based flux, organic acid flux and halogen-free flux.

Solvents are used to adjust the viscosity and printing performance of solder paste. Appropriate viscosity can ensure that the solder paste is evenly distributed during the printing process without problems such as drawing and collapse. The evaporation rate of the solvent will also affect the drying time and welding performance of the solder paste.

What is the role of solder paste in SMT patches?

In the SMT (surface mount technology) patch processing process, solder paste plays a vital role. It is not only used to bond components, but also the key to ensure the quality of electrical connections and mechanical strength.

1. Bonding components

One of the main functions of solder paste is to bond components. After the solder paste is accurately printed on the pads of the PCB (printed circuit board), the pins or contact points of the electronic components will be placed on the solder paste. The solder paste melts during the reflow soldering process to form a strong bond, ensuring that the components are stably attached to the PCB.

2. Provide electrical connection

Solder paste melts during the reflow soldering process and forms metal solder joints, which not only bond components but also provide electrical connections. Good electrical connections ensure the effective transmission of electrical signals on the PCB, which is the basis for ensuring the normal operation of electronic equipment.

The solder joints formed by the metal components (such as tin, silver, and copper) in the solder paste after melting have excellent conductivity, ensuring the reliability and stability of electrical connections.

3. Ensure mechanical strength

The mechanical strength of the solder joints is the key to ensuring the stable operation of electronic components in various environments. The solder joints formed by the solder paste after reflow soldering have sufficient mechanical strength to resist external stresses such as vibration, impact, and thermal expansion and contraction. This not only protects the components and PCB, but also improves the reliability and service life of the entire electronic equipment.

Is solder paste the same as flux?

Solder paste and flux are not the same. ‌

Although both solder paste and flux are materials used in the welding process, their functions and uses are different.

Solder paste is a paste-like viscous body, the main components of which include metal powder, rosin, organic acid, thixotropic agent, and activator, and is used for welding in SMT automatic mounting process.

Flux is a liquid, a mixture with rosin as the main component, which is used to remove oxides on the surface of solder and the base material to be welded, so that the metal surface reaches the necessary cleanliness, prevents the surface from re-oxidation during welding, reduces the surface tension of the solder, and improves welding performance.

In general, although both solder paste and flux are indispensable materials in the welding process, they have obvious differences in form, function, and usage.‌

What is the storage method of solder paste?

The correct storage method can extend the service life of the solder paste and ensure its stable performance.

1. Temperature control

Solder paste should be stored in a low temperature environment, usually 0-10℃. Excessive temperature will cause the solvent in the solder paste to volatilize, affecting its viscosity and printing performance. Avoid direct sunlight and high temperature environment during storage to prevent the solder paste from deteriorating.

2. Humidity control

Humidity has a great impact on solder paste. Excessive humidity will cause the solder paste to absorb moisture, affecting its printing performance and welding quality. The relative humidity of the storage environment should be controlled below 50% to ensure the stability of the solder paste.

3. Sealed storage

The solder paste should be stored in a sealed container to prevent oxygen and moisture from entering the air. The solder paste after opening should be used up as soon as possible, and the unused solder paste should be resealed and stored in a low temperature environment.

How to use solder paste correctly?

1. Reheating treatment

The solder paste stored in a low temperature environment should be reheated before use. The reheating time is usually 4-8 hours. During the reheating process, it should be avoided to be directly exposed to a high temperature environment to prevent the solvent in the solder paste from volatilizing. The solder paste after reheating should be fully stirred to ensure that the metal powder and flux are evenly distributed.

2. Printing process

Solder paste printing is a key process in SMT patch processing. During the printing process, the scraper pressure, printing speed and template opening size should be controlled to ensure that the solder paste is evenly distributed on the pad. The printed solder paste should have a good shape and should not have problems such as drawing and collapse.

3. Solder paste reflow

The solder paste reflow process is the process of melting the solder paste and forming a firm solder joint with the pad and component pin. The temperature curve should be controlled during the reflow soldering process to ensure that the solder paste melts at an appropriate temperature and fully wets the pad and pin. Too high or too low reflow temperature will affect the welding quality.

4. Solder joint detection

The quality of the solder joint is an important indicator for evaluating the welding effect. After the welding is completed, the solder joint detection should be carried out to check the shape, size and wettability of the solder joint. Qualified solder joints should have a smooth and complete surface without defects such as solder balls and cold solder joints.

Conclusion:

Solder paste plays a vital role in SMT patch processing. Its composition, selection, storage and use methods directly affect the welding quality and the performance of the final product. By understanding and mastering the relevant knowledge of solder paste, the quality of SMT patch processing can be effectively improved, and defects and rework rates can be reduced.

BEST Technology has rich experience and strict control standards in the selection and use of solder paste, and can provide customers with high-quality SMT patch processing services. If you have any questions about our products or services, please feel free to contact us. Choose BEST Technology , choose quality assurance.

What is a resistor?

A resistor is a current-limiting element that is used to limit the magnitude of the current through the branch to which it is connected. ‌

Resistors are a basic electronic component whose function is to hinder the flow of current. The resistance value of a resistor is fixed and generally consists of two pins. It is used to divide voltage, adjust signals, stabilize and adjust current and voltage in circuits.

Depending on whether the resistance value is variable, resistors can be divided into fixed resistors and variable resistors (potentiometers). The resistance value of a fixed resistor cannot be changed, while the resistance value of a variable resistor can be changed by adjusting the contact position. An ideal resistor is linear, that is, the instantaneous current through the resistor is proportional to the applied instantaneous voltage.

Resistors play an important role in circuits, whether as voltage dividers, current limiters, or in regulating the voltage and current in circuits.

How to identify resistor polarity?

Resistors are generally non-polar. Resistors are mainly used in circuits to limit current, divide voltage, shunt, etc. Their physical properties are completely determined by the materials used inside. Their main functions are voltage division, current shunting, current limiting, voltage reduction, impedance matching, etc. They do not care about how they are placed, so any type of basic resistor is non-polar.

Although in electrical analysis, people may assume that resistors have polarity to more intuitively understand the flow of current, this does not mean that resistors themselves have polarity. In fact, resistors can be regarded as a kind of extremely powerful wire with a specific power rating and resistance, and its function is to hinder or reduce current in both directions.

When identifying resistors, it is usually not necessary to consider their polarity because resistors do not have a fixed positive or negative pole. If you need to determine the direction of the current, you can judge it by the circuit symbol or other identification, but this has nothing to do with the polarity of the resistor itself.

Do any resistors have polarity?

Not all resistors have polarity. ‌

A resistor is an electronic component whose main function is to block the flow of electric current. In most cases, resistors themselves have no polarity, which means that both ends of the resistor can be considered as positive or negative potential. There are many types of resistors, including fixed resistors, adjustable resistors, and various sensitive resistors, but they do not have positive and negative polarity.

However, there are some special types of resistors, such as type A in the resistor array, which are polarized. But this does not mean that all resistors have polarity, because most resistors are non-polar. For example, type B in the resistor array has no polarity, and other types of resistors (such as C, D, E, F, etc.) have different internal resistor arrangements, but because they are not often used, the resistors usually referred to are generally non-polarized. ‌

In summary, although there are some special types of resistors that may have polarity, in most cases, resistors are electronic components without polarity. ‌

Do resistors have a positive and negative side?

Resistors have no positive and negative poles. ‌Resistors are passive electronic components whose main function is to block the flow of electric current without caring about the direction of the current. In the circuit, the direction of the current is indicated by an arrow, and the resistor itself does not change its impedance characteristics due to the change of the current direction.

Whether it is a fixed resistor, an adjustable resistor or a sensitive resistor, there is no distinction between positive and negative polarity. In AC circuits, there is no need to distinguish between positive and negative poles. In DC circuits, although the variable resistor is composed of a carbon film and a metal contact, it is necessary to clarify the direction of the current, but this does not mean that the resistor itself has positive and negative poles, but it means that the direction of the current needs to be clarified in DC circuits.

The concept of positive and negative poles is usually used for power supplies, batteries and certain specific components, where the positive pole is usually connected to a high potential and the negative pole is connected to a low potential. Power supplies and batteries have a positive and negative pole because of the potential difference, while resistors, as a passive component, have no potential difference, so there is no distinction between positive and negative poles.

In a circuit, when the power supply is connected, the current flows out from the positive pole, passes through the resistor, and finally returns to the negative pole, forming a current cycle, but this does not change the nature of the resistor itself, but is only part of the current path.

Can a resistor be connected in any direction?

Resistors can be connected in any direction. ‌Resistors are passive devices that do not distinguish polarity, so they can be installed at will without affecting their normal operation.

This characteristic of resistors makes the connection direction of resistors in the circuit very flexible. In addition, the connection direction of resistors is not affected by the direction of current, and even if the current direction changes, the performance and resistance of resistors will not change. Therefore, in practical applications, the connection direction of resistors can be freely selected as needed to meet specific circuit requirements.

Is there a wrong way to install a resistor?

If the welding is not firm or there are problems such as cold welding and short circuit, the resistor will lose connection or become abnormal, which will cause the circuit to work abnormally.

When installing the ground wire, if the grounding resistor is not installed correctly, and the appropriate time and conditions are not selected when measuring the grounding resistance, or the connection wire with the equipment is not disconnected when measuring the protective grounding resistance of the electrical equipment, the measurement results may be inaccurate.

In order to avoid these errors, it is very important to install and test the resistor correctly. When installing the resistor, ensure the welding quality, correctly measure the grounding resistance, and follow the correct installation steps and testing methods to ensure that the resistor can work properly.

How to wire a resistor to an LED?

When connecting a resistor to an LED, the resistor can be connected to the positive or negative terminal of the LED, as long as the polarity of the power supply is connected correctly. ‌

When using a resistor with an LED, the main function of the resistor is to limit the current to protect the LED from excessive current damage. Whether the resistor is connected to the positive or negative terminal of the LED, the key is to ensure that the current limit of the entire circuit is within the range that both the LED and the resistor can safely withstand. Specifically:

‌Connected to the positive terminal of the LED‌: In this configuration, the resistor is connected to the positive terminal of the LED, and the voltage applied to the two terminals of the LED is limited by controlling the current flowing through the resistor, thereby protecting the LED. This configuration is suitable for a variety of power supply voltages and LED types. As long as the polarity of the power supply is connected correctly, the position of the resistor (positive or negative) has little effect on the normal operation of the LED.

‌Connected to the negative terminal of the LED‌: Connecting the resistor to the negative terminal of the LED can also achieve the purpose of current limiting. This configuration also requires that the polarity of the power supply is connected correctly to ensure the safety of the circuit and the normal operation of the LED.

In practical applications, if you encounter the problem of frequent LED damage, it may be due to the quality problem of the LED itself or the circuit design defect.

In short, when connecting a resistor to an LED, the key is to ensure the safety of the entire circuit and the normal operation of the LED. By correctly selecting the position and value of the resistor and ensuring that the polarity of the power supply is correctly connected, the LED can be effectively protected from damage.

Conclusion:

Resistors play a vital role in circuits. They can protect various components of the circuit by controlling the magnitude of the current. With the evolution of products, various types of resistors have been generated, which can change their resistance values according to changes in the environment. Therefore, resistors are still very important until now. Understanding the role and use of resistors will help us understand circuits.

What is a PCB test?

PCB test is a technique that uses electronic testing instruments to detect the performance and quality of PCB (Printed Circuit Board) circuit boards. It is widely used in the electronics manufacturing industry to help manufacturers improve product quality and production efficiency.

The main purpose of PCB test is to ensure that all parts on the circuit board are properly connected and can still work properly under high voltage environments, while verifying whether the function of the circuit board is normal. Test methods include connectivity testing, withstand voltage testing, and functional testing, while inspection standards involve appearance inspection, size inspection, and performance inspection. In addition, PCB test also involves a series of professional techniques and methods, such as flying probe test, ICT test, FCT test, AOI test, etc., to ensure the electrical performance and structural integrity of the circuit board.

How to Test PCB?

PCB contains different components that affect the overall performance of electronic circuits. Tests are performed to check and optimize the status of these components using computerized machine software, simple electronic test equipment and tools, and even basic manual inspections.

1. Electrical test

2. Hole wall quality

3. Mechanical resistance test

4. Soldering quality

5. Cleanliness inspection, considering weather resistance, humidity and corrosion

6. Lamination, testing the ability of laminates to resist or heat peeling

Environmental testing is particularly necessary for PCBs used in humid environments.

What are the benefits of PCB test?

Error identification: The main benefit of PCB test is that it helps identify problems in PCBs. Whether the problem lies in functionality, manufacturability or other aspects, PCB test can identify problems in PCB design and layout.

Save time: Performing PCB test early helps save time in the long run by allowing designers to identify major issues during the prototyping phase. Comprehensive testing allows designers to quickly and easily identify the root cause of each issue and make adjustments so that they can move to production at a faster pace and reduce product lead times.

Reduce costs: PCB test avoids the waste of producing defective products by testing products using prototypes and small-scale components. By completing comprehensive testing early in the design process, designers can avoid the waste of producing defective PCBs, ensuring that the design is as perfect as possible before going into production.

Reduced returns: When PCB test is performed, the likelihood of selling defective products or products that do not meet performance standards is reduced, reducing the costs associated with refunding customers and handling defective goods.

Improved safety: Defective PCBs can cause fires, which can endanger people nearby. Pre-manufacturing testing also ensures that machines and workers are not damaged or injured due to poor design during the production process.

What are the types of PCB test?

1. In-circuit testing

In-circuit testing (ICT) is the most reliable type of PCB test available today. The high price reflects this – tens of thousands of dollars, although the cost depends on factors such as board and fixture size.

Also known as bed of nails testing, ICT fires and activates individual circuits on a board. In most cases, the test is designed to achieve 100% coverage, but actual coverage will be closer to 85-90%.

The test involves the use of fixed probes, whose layout matches the PCB design. The probes check the integrity of the soldered connections. A bed of nails tester simply pushes the board onto the probe bed to begin testing. Access points are pre-designed on the board to allow the ICT test probes to establish a connection with the circuit.

2. Flying probe testing

Flying probe testing is a tried and tested method that is cheaper than in-circuit testing. It is a non-powered test that checks for shorts, capacitance, inductance, diodes, and other problems.

The flying probe tester works by using needles connected to probes on an xy grid obtained from basic CAD. The ECM program coordinates to match the board and then runs the program connected to these test points.

In some cases, ICT makes flying probe testing unnecessary, but the PCB must be designed to fit the test fixture – which means a higher initial cost. ICT is faster and less error-prone than flying probe testing, and while flying probe testing may be cheaper initially, it may not actually be cost-effective for large orders. Finally, it is important to note that PCB flying probe testing does not power the board.

3. Automated Optical Inspection (AOl)

AOI is a contact-free visual inspection of printed circuit boards. AOI uses a camera and microscope to take photos of the PCB. The software then looks for inconsistencies between these photos and the board schematic. Technicians can thoroughly check each board and find any problems through this procedure.

The board is not powered during AOI, and it may not cover all part types. Due to these deficiencies, it should be used in conjunction with another test technology such as functional testing, flying probe testing, or ICT.

4. X-ray Inspection

As the name suggests, this type of test is essentially an inspection tool. It is also known as AXI. During this testing, X-ray technicians can detect defects early in the production process by carefully inspecting solder connections, internal traces, and barrels. Using X-ray inspection, invisible components can be inspected.

Due to the high density of SMT technology and the difficulty in locating connections in BGA and CSP (chip scale packages), more precise inspection techniques, such as those based on X-ray technology, are needed. Solder joints can be clearly seen in radiographs because they are made of materials with a higher atomic weight than other components on the board.

The main benefit of AXI technology is that it can identify every connection and solder joint, including those hidden by the package. In addition, solder joints can be inspected, highlighting any potential bubbles.

What are the difficulties in PCB test?

Increasing complexity: PCB designs are becoming more complex, with higher component density and smaller size, which makes it more difficult to access test points and increases the risk of undetected defects.

Cost: High-end test equipment such as X-ray inspection systems can be expensive to purchase and maintain. Testing also increases production costs, especially when test failures require rework.

Accuracy: Although the test equipment is designed precisely, errors may still occur due to calibration problems, software errors or human errors.

Conclusion:

PCB test is very important to the quality of the product. It ensures that the PCB, which forms the backbone of all electronic devices, operates normally and meets the required quality standards, effectively avoiding the impact of poor products, improving the quality of the finished product, and preventing problems when the product is used.

BEST Technology has a complete set of PCB test equipment and has very complete testing standards to ensure that each PCB finished product has extremely high quality. Choosing us, you will not need to worry about any PCB quality issues.

What is flux?

Flux: A chemical substance that can help and promote the soldering process in the soldering process, and at the same time has a protective effect and prevents oxidation reactions. Flux can be divided into solid, liquid and gas.

There are mainly several aspects such as “assisting heat conduction”, “removing oxides”, “reducing the surface tension of the material to be soldered”, “removing oil stains on the surface of the material to be soldered, increasing the soldering area”, and “preventing re-oxidation”. Among these aspects, the two most critical functions are: “removing oxides” and “reducing the surface tension of the material to be soldered”.

Do you apply flux before or after soldering?

Use flux before soldering printed circuit boards. ‌

During the soldering process of printed circuit boards, the main purpose of using flux is to improve soldering performance and help the metal avoid the formation of an oxide film that hinders solder wetting when heated, thereby promoting the formation of solder-metal alloys and avoiding the occurrence of cold soldering and false soldering.

Flux can be applied to the printed circuit board before soldering, or it can be used as part of the solder during the soldering process, such as solder paste or solder oil. When tinning the pins of components, rosin should be used as the flux, and if the printed circuit board is already coated with rosin solution, then no additional flux is required during soldering.

After using flux, make sure to wipe off the residual flux at the soldering site after soldering to avoid potential damage to electronic components and circuit boards.

In addition, the preparation work before soldering includes thoroughly cleaning the copper foil surface and then applying rosin water to protect the copper foil and help soldering. This step is performed before soldering to ensure the smooth progress of the soldering process. Therefore, the correct approach is to use flux before soldering printed circuit boards to ensure the quality and reliability of soldering.

How much flux to use when soldering?

When soldering printed circuit boards, the amount of flux used needs to be determined according to the specific soldering method and the type of flux. For wave soldering flux, when using brushing and foaming methods, the specific gravity of the flux should be controlled between 0.82-0.84 (specific gravity of liquid rosin flux stock solution).

During the soldering process, the specific gravity of the flux needs to be measured regularly. If the specific gravity is found to increase, it should be adjusted to the normal range with diluent in time, but the diluent should not be added too much to avoid affecting the soldering quality.

For the quantitative spraying method, the key is that the nozzle can control the spray volume. The nozzle should be cleaned frequently to ensure that the spray hole is not blocked. The spray pressure should be controlled at 0.2-0.3Mpa, the flux pressure should be controlled at 0.4±0.05Mpa, and the spray flow rate should be controlled at 20-35ml/min.

In addition, different types of flux formulas are also different. For example, rosin liquid can be made by mixing rosin blocks and alcohol in a ratio of 1:3. For the flux of printed circuit boards, you can directly use rosin water, and apply the prepared rosin water directly on the surface of the printed circuit board or the solder joints.

When using flux, you should also pay attention to the following points:

Put the bottle cap on immediately after use to prevent the flux from being in contact with air for a long time and causing oxidation reaction or absorbing water vapor in the air to cause the concentration to decrease.

Regularly replace the flux that has been stored for too long, because long-term storage will cause the flux composition to change and the activation performance to deteriorate, affecting the welding quality.

Clean it after welding, because the insulation performance of the flux will drop sharply at high temperature, and the residue may affect the heating components, and in severe cases may cause short circuits.

In summary, the amount of flux used in printed circuit board welding needs to be determined according to the specific welding method and flux type, and pay attention to the use and storage conditions of the flux to ensure welding quality and safety.

What happens if you use too much flux when soldering?

First, the main functions of flux include assisting heat conduction, removing oxides, reducing the surface tension of the material being soldered, removing oil stains on the surface of the material being soldered, increasing the soldering area, and preventing reoxidation.

However, excessive use of flux can lead to corrosion and electromigration. This is because improper use of flux, such as excessive use, can create more favorable conditions for potential chemical corrosion reactions.

In addition, if the flux used is not well controlled, resulting in excessive use of flux, more flux residue will be left, which creates more favorable conditions for potential chemical corrosion reactions.

Therefore, it is very important to control the amount of flux used to avoid negative effects on soldering quality and reliability.

What happens if I don’t use flux?

If flux is not used on printed circuit boards, it may lead to reduced soldering quality, increased soldering difficulty, and affect the performance and reliability of the circuit.

1. Increased soldering difficulty: Without flux, the solder may be difficult to flow to the soldering point, resulting in loose soldering, prone to cold soldering or poor soldering.

2. Reduce welding quality: Without the help of flux, the soldering point may not be smooth enough, with burrs or unevenness, which may affect the normal operation of the circuit.

3. Affect circuit performance and reliability: Flux can reduce the resistance of the soldering point and improve the conductivity of the circuit. Without flux, the resistance of the soldering point may increase, affecting the performance and stability of the circuit.

In addition, the flux can also prevent oxidation to a certain extent, protect the soldering point from the influence of the external environment, thereby improving the life of the circuit. Therefore, in the soldering process of printed circuit boards, it is very important to use the soldering flux correctly.

What is an alternative to soldering flux?

Alternatives to printed circuit board soldering flux include no-clean soldering flux, special solder resist for printed circuit boards, water-based cleaning agents and dry ice cleaning technology. ‌

1. No-clean soldering flux is a new type of soldering flux that does not contain halide activators. It does not need to be cleaned after use, which can save investment in cleaning equipment and cleaning solvents, while reducing the emission of waste gas and wastewater, and the pollution to the environment is also reduced accordingly.

2. The main function of the ‌PCB solder mask‌ is to prevent “wiring” and short circuits during wave soldering and protect the PCB permanently. In addition, it can save solder, reduce the weight of the PCB, and reduce costs.

3. As a new type of cleaning medium, the ‌water-based cleaning agent‌ achieves cleaning through the wetting, dissolution, emulsification, saponification, chelation and other effects of the surfactants, emulsifiers, penetrants, etc.

4. The ‌dry ice cleaning technology‌ uses extremely low-temperature dry ice particles to spray onto the treated object under the action of compressed air, so that the dirt is rapidly frozen to brittleness and burst, and then vaporized to take away the dirt.

These substitutes have their own characteristics and are suitable for different application scenarios and technical requirements. When choosing, specific process requirements and cost-effectiveness must be considered.

What does rosin do when soldering?

In the process of printed circuit board soldering, rosin plays a vital role. It is mainly used as a flux to help the soldering process be smoother and more efficient. The role of rosin is reflected in the following aspects:

‌Removing oxide film‌: Rosin can remove the oxide film formed on the copper surface due to contact with air. These oxide films will prevent the tin from wetting the copper wire, thus affecting the quality of welding.

‌Preventing re-oxidation‌: Rosin can not only remove the oxide film, but also prevent the soldering surface from re-oxidizing during the welding process, which helps to maintain the stability and reliability of the welding point.

‌Isolating air‌: Under high temperature conditions of welding, rosin can isolate the air and prevent oxidation of the metal surface.

In summary, rosin plays an important role in the soldering process of printed circuit boards. Through its fluxing effect, it improves the quality and reliability of soldering and is one of the indispensable materials in electronic manufacturing‌.

Conclusion:

Flux is a key part of the soldering process. Without it, your solder will not flow smoothly through the joint and the solder will not adhere properly to the various components on the circuit board. High-quality flux is necessary to produce good solder joints.

BEST Technology is a professional PCB circuit board manufacturer with many years of experience in PCB circuit board welding. The circuit boards it produces are of extremely high quality. We have the most extensive experience to deal with all aspects of PCB welding issues.

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