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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
Poor solderability of circuit board holes will result in virtual soldering defects, affecting the parameters of components in the circuit, leading to unstable conduction of multi-layer board components and inner wires, and causing the entire circuit function to fail. The so-called weldability refers to the property of the metal surface being wetted by molten solder, that is, the formation of a relatively uniform and continuous smooth attached film on the metal surface where the solder is located. The main factors affecting the solderability of printed circuit boards are: (1) the composition of the solder and the properties of the soldered material. Solder is an important component of the welding chemical treatment process, which is composed of chemical materials containing flux. The commonly used low melting point eutectic metals are Sn-Pb or Sn-Pb-Ag. The impurity content should be controlled in a certain proportion to prevent the oxide produced by impurities from being dissolved
The circuit board and components undergo warping during the welding process, resulting in defects such as virtual soldering and short circuits due to stress deformation. Warping is often caused by temperature imbalance between the upper and lower parts of a circuit board. For large PCBs, the weight of the board itself can also cause warping. A regular PBGA device is about 0.5mm away from the printed circuit board. If the device on the circuit board is large, as the circuit board cools down and returns to its normal shape, the solder joints will be under stress for a long time. If the device is raised by 0.1mm, it is enough to cause a virtual solder open circuit. In terms of layout, when the circuit board size is too large, although welding is easier to control, the printed lines are longer, the impedance increases, the noise resistance decreases, and the cost increases; If it is too small, the heat dissipation will decrease, and welding will be difficult to control, making it easy
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 wirin
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
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
On PCBs, nickel is used as a substrate coating for precious and base metals. The deposition layer of low stress nickel on PCB is usually prepared using modified Watt nickel plating solution and some amino sulfonic acid nickel plating solution with stress reducing additives. What are the common problems encountered when using PCB nickel plating solution, as analyzed by CITIC Huawei? 1、 Temperature - Different nickel processes use different plating bath temperatures. In nickel plating solutions with higher temperatures, the obtained nickel coating has low internal stress and good ductility. The general operating temperature is maintained at 55-60 degrees Celsius. If the temperature is too high, nickel salt hydrolysis will occur, causing pinholes in the coating and reducing cathodic polarization. 2、 PH value - The pH value of nickel plating electrolyte has a significant impact on the performance of the coating and electrolyte. The pH value of PCB nickel plating electrolyte is genera
In PCB sampling, nickel is used as a substrate coating for precious and base metals. For some surfaces with heavy load wear, using nickel as the gold substrate coating can greatly improve wear resistance. When used as a barrier layer, nickel can effectively prevent the diffusion between copper and other metals. Next, CITIC Huawei will explain the causes and solutions of PCB nickel plating process faults: 1、 Ma Keng: Ma Keng is the result of organic pollution; If the stirring is poor, bubbles cannot be expelled and pits will form. Large pits usually indicate oil contamination, and wetting agents can be used to reduce their impact. Small pits are called pinholes, which can be caused by poor treatment, metal impurities, low boric acid content, and low plating temperature. Bath maintenance and process control are key, and anti pinhole agents should be used as process stabilizers to supplement. 2、 Roughness and burrs: Roughness indicates that the solution is dirty, which can be correc
The volume of electronic products is becoming increasingly thin and short, and directly stacking holes on through blind holes is a design method to achieve high-density interconnection. To achieve good hole stacking, the first step is to ensure the flatness of the hole bottom. There are several typical methods for making flat hole surfaces, and electroplating hole filling process is one of the representative ones. The electroplating hole filling process can not only reduce the necessity of additional process development, but also be compatible with current process equipment, which is conducive to achieving good reliability. So, what factors affect the PCB electroplating hole filling process? In PCB sampling, the influence of substrate on electroplating hole filling cannot be ignored, generally including factors such as dielectric layer material, hole shape, thickness to diameter ratio, and chemical copper coating. (1) Medium layer material. The material of the dielectric layer ha
The through hole plays a role in connecting and conducting circuits, and the development of the electronics industry has promoted the development of PCBs, resulting in the emergence of plug hole technology. In order to meet the customer's requirements, the process of conducting and plugging holes can be described as diverse, with a particularly long process flow and difficult process control. So, how is the process of plugging through holes in PCB circuit boards achieved? Let's take a look together with the editor: 1、 Plug hole process after hot air leveling This process flow is: board surface resistance welding → HAL → plug hole → curing. Production is carried out using a non plug hole process, and after hot air leveling, aluminum mesh plates or ink blocking nets are used to complete the plug holes of all fortresses. Plug ink can be used as photosensitive ink or thermosetting ink. This process flow can ensure that the guide hole does not fall off oil after hot air leveling, but
(1) There should be a reasonable direction: such as 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. Its purpose is to prevent mutual interference. (2) Choose a good grounding point: For example, the multiple ground wires of the forward amplifier should be merged before connecting to the main ground, etc. (3) Reasonably arrange the power filter/decoupling capacitors: Generally, only a few power filter/decoupling capacitors are drawn in the schematic diagram, but they are not indicated where they should be connected. In fact, these capacitors are designed for switching devices or other components that require filtering/decoupling, and they should be arranged as close to these components as possible. (4) There is a particular emphasis on lines: if conditions permit, lines that are wide will never be thin; High voltage and high-frequency lines
What are the design requirements for PCB printed circuit boards in PCB sampling? Let's take a look together: 1. Accurate This is the most basic and important requirement for printed circuit board design. Accurately implement the connection relationship of the electrical schematic diagram to avoid errors such as "short circuit" and "open circuit". Generally, products need to undergo more than two rounds of trial production and modification, while CAD software with strong functions has inspection functions to ensure the correctness of electrical connections. 2. Reliable A correctly connected circuit board may not necessarily have good reliability, such as improper selection of boards, incorrect board thickness and installation fixation, improper component layout and wiring, etc., which may cause the PCB to not work reliably. 3. Reasonable A printed circuit board component is closely related to the rationality of the printed circuit board, from manufacturing, inspection, assembl
The circuit board sampling of circuit board manufacturers generally refers to the electronic products being sent to the circuit board manufacturer for processing into circuit boards for testing after the engineer completes the PCB layout design. Because it is a newly developed product, many functions are not yet perfect, and there are still many functions that need to be debugged. Only after debugging is qualified can batch production be carried out. If debugging is not qualified, it is necessary to revise, sample, and debug again, reducing a lot of unnecessary hemp in the later stage The quantity of samples varies depending on the delivery time of the samples. Generally speaking, for an ordinary single and double-sided board, it is not urgent, with a quantity of less than 10 pieces and a standard process. The scale is within 100 * 100mm, and it usually costs only 50 yuan. However, if your quantity is larger than this, and the delivery time needs to be expedited, the price will va
Generally, a well made PCB board diagram needs to be processed and manufactured by the board manufacturer. After the sample is completed, technicians will weld the components together, and finally assemble them into the shell and package them to form a complete product. So what relevant document parameters and explanations are required for PCB sampling to be provided to the manufacturer? Let me explain them in detail below. What are the relevant document parameters and explanations provided to the manufacturer for PCB sampling requirements 1. PCB sampling data: To clarify what kind of manufacturing data is required for PCB, the most common method currently is to use FR4, and the primary data is epoxy resin peeled fiber cloth board. 2. Layer: To clarify the number of layers you manufacture for PCB boards. (The manufacturing layers of PCB boards vary, and the price may vary, while the sampling process for PCB circuit boards is completely different.) 3. Solder resistance color: The
1. The thickness of gold is much thicker than that of gold plating, and sinking gold will produce a golden yellow color that is more yellow than plating, which is more satisfying for customers. 2. Compared to gold plating, sinking gold is easier to weld and will not cause welding defects, leading to customer complaints. The stress on the sinking gold plate is easier to control, which is more conducive to the processing of products with bonding. It is precisely because sinking gold is softer than plating gold that sinking gold plates make gold fingers less wear-resistant. 3. As long as there is nickel gold on the solder pad of the sinking gold plate, the signal transmission in the skin effect will not be affected by the copper layer. 4. Compared to gold plating, sinking gold has a denser crystal structure and is less prone to oxidation. 5. As the wiring becomes denser, the line width and spacing have now reached 3-4 MIL. Gold plating is prone to short circuits in the gold wire.
1、 Quality requirements and key control points for PCB etching process: 1. There should be no residual copper in the sample production of PCB boards, especially double-sided boards, which should be noted. 2. There must be no residual adhesive present, otherwise it will result in exposed copper or poor adhesion of the coating. 3. The etching speed should be appropriate, and it is not allowed to show the thinning of the line caused by excessive etching. The etching line width and total pitch should be the focus of our station's control. 4. The dry film on the solder joints of the circuit shall not be washed away or cracked. 5. After etching and peeling, the board should not have any oil stains, impurities, copper skin warping or other poor quality. 6. When placing the board, attention should be paid to preventing jamming and oxidation. 7. It should be ensured that the etching solution is evenly distributed to prevent uneven etching of different parts on the front and back or t
With the continuous development of the electronics industry, various electronic products are emerging one after another. Often, some customers demand unconventional thickness boards, such as 2.0mm, 2.4mm, 2.5mm, 3.0mm thick, etc. Can 3.0mm thickness boards be produced? The answer is revealed below, and the editor will explain it in detail below. In order to ensure the integrity of product functionality, many customers choose thicker boards for production when their boards are used on equipment or when the components on the boards are heavy. The normal board thicknesses we produce are 0.6mm, 0.8mm, 1.0mm, 1.2mm, and 1.6mm. Some special products require thicker PCB boards. Use thicker PCB boards. Can we ultimately make a 3.0mm thick PCB sample. The answer is certain, it can be produced. Our company often produces this type of board, and producing PCBs of this thickness is no longer a challenge in the industry. Only engineers need to pay attention when planning. When planning, it i
After using printed boards in electronic devices, due to the consistency of similar printed boards, errors in manual wiring are avoided, and electronic components can be automatically inserted or pasted, soldered, and inspected, ensuring the quality of electronic devices, improving labor productivity, reducing costs, and facilitating maintenance. Development: Printed circuit boards have evolved from single-layer to double-sided, multi-layer, and flexible, and still maintain their respective development trends. Due to the continuous development towards high precision, high density, and high reliability, as well as the reduction of volume, cost, and performance, printed circuit boards still maintain strong vitality in the future development of electronic equipment engineering. The discussion on the development trend of future printed circuit board production and manufacturing technology at home and abroad is basically consistent, which is to develop towards high-density, high-prec
A printed board is better when installed upright, and the distance between boards should generally not be less than 2cm. Moreover, the arrangement of devices on the printed board should follow certain rules: For equipment that uses free convection air cooling, it is better to arrange integrated circuits (or other devices) in a longitudinal manner; For equipment that uses forced air cooling, it is better to arrange integrated circuits (or other devices) in a horizontal and elongated manner; Devices on the same printed circuit board should be arranged in zones according to their heat generation and heat dissipation degree as much as possible. Devices with low heat generation or poor heat resistance (such as small signal transistors, small-scale integrated circuits, electrolytic capacitors, etc.) should be placed upstream (at the inlet) of the cooling airflow, while devices with high heat generation or good heat resistance (such as power transistors, large-scale integrated circuits
1. Component packaging (1) Pad spacing If it is a new device, you need to draw the component packaging yourself to ensure proper spacing, as the pad spacing directly affects the soldering of the component. (2) Through-hole size (if any) For plug-in devices, sufficient margin should be reserved for through-hole size, generally not less than 0.2mm is more appropriate. (3) Contour screen printing The contour screen of the device is slightly larger than its actual size, ensuring that the device can be installed smoothly. 2. PCB board layout (1) IC should not be placed near the board edge. (2) Components of the same module circuit should be placed close to each other For example, decoupling capacitors should be placed close to the power pins of the IC, and components that make up the same functional circuit should be prioritized and placed in one area with clear hierarchy to ensure the implementation of functions. (3) Arrange the position of sockets according to actual instal
(1) Terminating resistor It is better to connect a matching resistor at the end of a high-speed line or a digital signal line with higher frequency and longer routing. (2) Connect the input signal line to a small capacitor in parallel It is better to connect the signal line input from the interface to a small capacitor at the interface level near the interface. The size of the capacitor is determined by the strength and frequency of the signal, and cannot be too large, otherwise it will affect the integrity of the signal. For low-speed input signals, such as button inputs, a 330pF small capacitor can be selected, as shown in Figure 2. Figure 2: PCB board design_ Connect the input signal line to a small capacitor Figure 2: PCB board design_ Connect the input signal line to a small capacitor (3) Driving ability For example, a switch signal with a high driving current can be driven by a transistor; For buses with large fan outs, buffer drivers can be added.
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