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Have you noticed that now more and more of our lighting is using led lighting.What is LED? Compared to the traditional light bulbs, LEDs have lower power consumption, longer lifetime and higher energy efficiency. In the PCB industry,when we say LED PCB, it refers to the pcb used for LED lighting, if you are looking for a suitable LED PCB for your lighting system, this article may bring you something. WHAT ARE LEDS COMPOSED OF?LED is an initial light-emitting diode that produces light when an electric current passes through. LEDs typically have negative and positive electrodes, which generate light in the visible light region.The LEDS are glued to the PCB by soldering process and have electrical connections for lighting.Since light-emitting diodes dissipate a lot of heat when they are in use, when you are designing LED, the metal core is usually the best choice for LED PCB, it is because that it dissipates heat more faster. Among them, the metal material aluminum is the most widely used
Welding is an important process in PCB circuit board sampling. We often encounter many welding defects when making PCBs. So, what are the common welding defects of PCB circuit boards? 1. False soldering: There is a clear black boundary between solder and component leads or copper foil, and solder is concave towards the boundary. Hazard: The circuit board cannot function properly. Reason: 1) Component leads are not cleaned properly, not tin plated or oxidized; 2) The printed board was not cleaned properly and the quality of the soldering flux sprayed was poor. 2. Solder accumulation: The solder joint structure is loose, white, and dull. Hazard: Insufficient mechanical strength, possible false soldering. Reason: 1) Poor solder quality; 2) Insufficient welding temperature; 3) Loose component leads. 3. Excessive solder: The solder surface is convex. Hazard: Waste solder and may contain defects. Reason: The solder was evacuated too late. 4. Insufficient solder: The welding are
Many special components are often used in PCB layout, and if the layout is not handled properly, it will directly affect the performance and quality of the PCB circuit board. So, what are the layout requirements for special components on PCB circuit boards? 1. Layout requirements for crimping devices (1) There should be no components greater than 3mm around the crimping device surface, and no welding components should be present around 1.5mm; There must be no components within a distance of 2.5mm from the center of the pin hole of the crimping device on the opposite side of the crimping device. (2) There should be no components within 1mm around the crimping device. 2. Layout requirements for thermal sensitive devices (1) Thermal sensitive devices (such as electrolytic capacitors, crystal oscillators, etc.) should be kept away from high thermal devices as much as possible. (2) The thermal sensitive device should be tightly attached to the tested component and away from the hi
PCB circuit boards can be divided into single-sided, double-sided, and multi-layer. Multilayer boards refer to circuit boards with more than 4 layers, and currently there are over 100 layers of PCBs. Why are PCB multilayer boards even numbered? 1. Relatively speaking, even layer PCBs do have more advantages than odd layer PCBs. Due to the lack of a layer of medium and foil, the raw material cost of odd layer PCBs is slightly lower than that of even layer PCBs, but its processing cost is significantly higher than that of even layer PCBs. Odd layer PCBs require the addition of non-standard laminated core bonding processes on top of the core structure process. Before lamination bonding, the outer core requires additional processing, which increases the risk of scratches and etching errors on the outer layer. 2. Odd layer circuit boards are prone to bending. When the PCB cools down after the multi-layer circuit bonding process, different lamination tensions can cause the PCB to bend.
The question that many newcomers ask the most is: why are the vast majority of PCB board colors green? Today, the PCB engineer will come to answer this question for you. 1. Green ink is currently the most widely used and long-lasting ink, and it is also the cheapest in the market. Therefore, green is widely used as the main color for PCB products by many manufacturers. 2. Usually, during the production of PCB circuit boards, there are several processes that must go through the yellow light chamber, because green has a better effect in the yellow light chamber than other colors. In addition, when soldering components in SMT, PCB circuit board production needs to go through solder paste and lamination, as well as the final AOI calibration process. Optical positioning calibration is required, and boards with a green background color have better recognition effect on the instrument. 3. The production of PCB circuit boards may not necessarily be green, it depends on the color that the
Many customers often ask: What are the common problems encountered in PCB circuit board design? Let professional PCB manufacturers tell you below. 1. Why do we try not to split across power sources when wiring? Because the signal spans different power layers, its return path becomes longer and more susceptible to interference. Of course, low-speed signals are acceptable, but high-speed signals should be carefully checked and avoided crossing as much as possible. 2. Some boards may have external input and output interfaces, and if their grounding design is not good, it can also affect normal operation and become a source of external electromagnetic interference, sending out the noise inside the board. Generally speaking, a separate interface ground will be separated and connected to the signal ground through thin wiring, which can be connected in series with a resistance of 0 ohms or a small resistance value. Common grounding symbols: PE, PGND, FG - protective grounding or casin
PCB layout and design have a significant impact on the way a circuit works, therefore, if printed circuit boards are designed in an effective manner, the circuit will work more reliably within its specification range. So, what are the issues to pay attention to in the layout and design of PCB circuit boards? 1. PCB design equipment For commercial development programs, CAD and computer-aided design packages may be required due to complexity. The functionality of PCB software varies greatly. Budget and even free software provide basic functions, while high-end software packages allow for more features to be included in the design. Simulation, complex routing, and more features are available. 2. Circuit schematic capture The first step in PCB design is to capture the circuit schematic. The circuit can be input into the schematic capture tool and can also be simulated during this stage. For applications such as RF circuit design, circuit simulation can lead to more optimization of
PCB design is an important step before PCB production. If not designed well, it will directly affect the performance and quality of the circuit board, causing the entire circuit board to be scrapped; Layout of components is an important aspect of PCB design. So, what are the requirements for PCB design and layout of components? 1. Aesthetics When designing a PCB, it is not only important to consider the orderly placement of components, but also to consider the graceful and smooth wiring. 2. Force The circuit board should be able to withstand various external forces and vibrations during installation and operation: it should have a reasonable shape, and the positions of various holes on the board should be arranged reasonably; Generally, the distance between the hole and the board edge should be at least greater than the diameter of the hole; It should also be noted that the weakest section of the plate caused by irregular holes should also have sufficient bending strength. 3.
Rigid flexible combination board is a method of laminating a flexible circuit substrate and a rigid circuit substrate together, which has both the rigidity of a hard board and the flexibility of a soft board. So, what issues should be paid attention to when making rigid flexible composite boards? 1. The design of rigid flexible composite plates usually changes from rigidity to flexibility, and then to rigidity. The rigid region generally has more layers than the flexible region, and the material is transferred from FR-4 to polyimide in the transition region. When intersection occurs, the overlap between rigid and flexible materials needs to keep the holes away from the transition area to maintain integrity. In addition, many rigid and flexible designs incorporate reinforcing materials such as stainless steel or aluminum to provide additional support for connectors and components. 2. Flexible circuits have bent wires that can affect wiring. Due to possible material stress, it is n
Introduce the relevant content and situation of printed circuit boards to help everyone improve their understanding. Let's read the following content together with the editor. Printed circuit boards (PCBs) are convenient thin sheets used to accommodate interconnected electrical components in a simple, convenient, and economical manner. They are used as physical supports for installing and connecting different electrical components. The PCB is made of glass fiber, composite epoxy resin or any other composite material, and has a metal coated surface. They have etching made of metals and acids to create circuits through different integrated circuits (ICs) and other components on circuit boards. Solder connects ICs and other components to the surface of the circuit board. The copper tracks in the circuit board reduce the possibility of short circuits, misalignment, or misaligned wires. In this way, all components are firmly fixed to the circuit board without the need for complex wir
In the field of PCB, there are often many English terms that industry insiders may find difficult to fully recognize. How much do you know about PCB terminology? Let me introduce some commonly used terms in the PCB field to you: 1. FR4 In most cases, the glass fiber substrate for PCBs generally refers to the material "FR4". The solid material "FR4" gives PCB hardness and thickness. Some cheap PCBs are made of materials such as epoxy resin or phenol, lacking the durability of FR4, but they are much cheaper. Phenolic substances have a lower thermal decomposition temperature, and excessive welding time can lead to their decomposition and carbonization, and emit unpleasant odors. 2. Copper The thin copper foil layer on a PCB is pressed onto the substrate through heat and adhesive during production. On double-sided boards, copper foil is pressed onto both sides of the substrate. When we mention "double-sided board" or "two-layer board", we refer to two layers of copper foil on a th
Soft hard combination board refers to a circuit board with FPC and PCB characteristics that is formed by combining flexible circuit boards and hard circuit boards in PCB sampling through pressing and other processes according to relevant process requirements. So, what are the application areas of soft and hard combination boards? 1. Industrial use: including industrial, military, and medical fields. The requirements for soft and hard boards in these fields include high reliability, high accuracy, low impedance loss, complete signal transmission quality, and durability. Due to the complexity of the manufacturing process and low output, the production cost is high. 2. Mobile phone: The application of a soft and hard combination board in a mobile phone, commonly including the turning point of a foldable phone, image module, buttons, and RF module. 3. Consumer electronics products: The software and hardware boards used in DSC and DV are the most representative. In terms of performan
Copper clad laminate (CCL) is the most widely used and important basic board for PCB sampling; It consists of three parts: copper foil, reinforcing material, and adhesive. Its function is to support various components and achieve electrical connections or insulation between them. So, what are the classifications of PCB foil plates? 1. Classification by reinforcement material The most commonly used reinforcement materials for laminated sheets are alkali free, fiberglass products, or paper. Therefore, laminates can be divided into two categories: glass cloth based and paper based. 2. Classification by adhesive type The main adhesives used for laminated sheets include phenolic, epoxy, polyester, polyimide, polytetrafluoroethylene resin, etc. Therefore, laminated sheets are also divided into phenolic, epoxy, polyester, polyimide, and polytetrafluoroethylene laminated sheets accordingly. 3. Classification based on substrate characteristics and usage According to the degree of comb
The so-called copper coating refers to using the idle space on the PCB as a reference plane, and then filling it with solid copper. These copper areas are also known as copper filling. Copper coating can be divided into large-area copper coating and grid copper coating. Next, let professional PCB manufacturers provide you with a detailed understanding of the basic knowledge of PCB circuit board copper coating: 1、 Precautions for copper coating: 1. Single point connection in different locations: connected through a 0 ohm resistor, magnetic bead, or inductor. 2. The copper coating near the crystal oscillator is used as a high-frequency emission source in the circuit. The crystal oscillator should be surrounded by copper coating, and then the outer shell of the crystal oscillator should be grounded separately. 2、 What are the benefits of copper coating? 1. Copper coating can reduce ground wire impedance and improve anti-interference ability; 2. Reduce voltage drop and improve po
The reasons for the warping of printed circuit boards are, on one hand, the possible warping of the substrate used, and on the other hand, the warping caused by thermal stress, chemical factors, and improper processing during the processing. So, what are the preventive measures for warping of printed circuit boards? 1. Prevent improper inventory methods from causing substrate warping. (1) During the storage process, if the humidity in the inventory environment is high, the copper clad plate will increase warping due to moisture absorption. So for copper clad panels without moisture-proof packaging, attention should be paid to warehouse conditions, minimize warehouse humidity, and avoid bare placement of copper clad panels. (2) Improper placement of copper clad panels can increase warping. If placed vertically or with heavy objects pressed on the copper clad plate, it will increase the warping deformation. Solution: Improve the storage environment, eliminate vertical placement,
PCB wiring is very important and has a significant impact on the product's lifespan, stability, and electromagnetic compatibility. If the wiring of the circuit board is unreasonable, the product performance will be greatly reduced. Below, we will introduce several special methods for PCB circuit board wiring, hoping to be helpful to you. 1. Right angle wiring: The impact of right angle routing on signals is mainly reflected in: (1) Corners can be equivalent to capacitive loads on the transmission line, slowing down the rise time; (2) Impedance discontinuity can cause signal reflection; (3) The EMI generated by the right angled tip will become a focus of high-speed circuit design in the field of RF design above 10GHz. 2. Differential wiring The advantages of differential signal compared to ordinary single ended signal wiring are as follows: (1) Strong anti-interference ability. Because the coupling between two differential routing lines is good, when there is external noise
PCB design is particularly important as it appears in almost every electronic device. So, what are the common mistakes in PCB circuit board design? 1、 Character shuffling Including character cover solder pads and SMD solder pads, which brings inconvenience to printed board testing and component welding; The character design is too small, making it difficult to screen, and it can cause characters to overlap and be difficult to distinguish. 2、 Abuse of graphic layers 1. Some useless connections were made on some graphics layers. 2. When designing, it is easy to draw and label the lines that are common to each layer using the Board layer. However, when conducting photo data, the circuit is broken due to missing lines due to the absence of a Board layer. 3、 Overlap of pads 1. The overlap of solder pads (excluding surface mounted solder pads) means the overlap of holes, which can cause damage to the holes during the drilling process due to multiple drilling at one location. 2. T
PCB is the fundamental electronic component of all electronic circuit designs, and the design of PCB circuit boards is also a must for engineers to understand. So, what methods should be mastered in PCB circuit board design? 1. There should be a reasonable direction The best direction is in a straight line, but it is generally not easy to achieve, and the most unfavorable direction is in a circular shape. For input/output, AC/DC, strong/weak signals, high-frequency/low-frequency, high-voltage/low-voltage, etc., their direction should be linear (or separated) and should not blend with each other, with the aim of preventing mutual interference. 2. Choose a good grounding point In general, it is required to have a common ground connection, such as: the multiple ground wires of the forward amplifier should be merged and then connected to the main ground, etc. In reality, it is difficult to fully achieve due to various limitations, but efforts should be made to follow them. 3. Reas
High frequency PCB circuit design is a very complex design process, and its wiring is crucial for the entire design! So, what are the wiring methods for high-frequency PCB circuits? 1. Multilayer board wiring In the PCB layout stage, choose a reasonable number of layers of printed circuit board size, fully utilize the middle layer to set shielding, better achieve nearby grounding, effectively reduce parasitic inductance and shorten signal transmission length, while also significantly reducing signal cross interference. 2. The less bent the leads between electronic device pins, the better It is best to use a full straight line as the lead wire, which requires a turning point. A 45 degree broken line or arc turning point can be used to meet this requirement, but it can reduce the external emission and mutual coupling of high-frequency signals. 3. The shorter the lead between device pins, the better The radiation intensity of a signal is directly proportional to the length of th
There are significant differences in the usage scenarios, products, performance, materials, areas, and other aspects of PCB boards, resulting in significant changes in the types of components used, the thickness of connecting wires, and the density of wiring. So, what factors need to be considered when selecting PCB boards? 1. For general electronic products, use FR4 epoxy glass fiber substrate; For use with high ambient temperatures or flexible circuit boards, polyimide glass fiber substrates are used; For high-frequency boards, polytetrafluoroethylene glass fiber substrate needs to be used; For electronic products with high heat dissipation requirements, metal substrates should be used. 2. Plates with higher glass transition temperature (Tg) should be appropriately selected, and the Tg value should be higher than the circuit operating temperature. 3. Low coefficient of thermal expansion (CTE) is required for the board. 4. High heat resistance of the board is required. General
PCB screen printing is an important process in PCB production and also determines the quality of the finished PCB board. So, what are the specifications and requirements for PCB screen printing? 1. All components, installation holes, and positioning holes have corresponding silk screen markings. In order to facilitate the installation of the finished board, the installation holes on the PCB are marked with H1, H2,... Hn by screen printing. 2. Silk screen characters should follow the principle of going from left to right and from bottom to top as much as possible; For devices with polarity such as electrolytic capacitors and diodes, try to maintain consistent orientation within each functional unit. 3. There is no silk screen on the solder pads of the devices and the tin channels that need to be coated with tin, and the device tag number should not be obstructed by the devices after installation; The silk screen should not be pressed on the through hole or solder pad to avoid los
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