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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
The principle diagram is a drawing composed of electrical symbols to analyze the principle of circuit. It has an indispensable role in product debugging, maintenance, and improvement. Principle diagram reversing and positive design is the opposite. The positive design is first designated by the principle diagram, and then the PCB design is performed according to the schematic diagram. The schematic diagram is convenient to analyze the product and assist the later product prototype to debug production or improve the upgrade. In the process of product reverse technology research and imitation development, the production of the BOM list and the position diagram of the patch, the production of the coordinates of the component of the SMT patch machine are all later model welding, patch processing, and complete prototype design and assembly production. Link. BOM (Material List) is the basis for the purchase of device materials, which records the various components, modules and other sp
In high -speed design, the characteristic impedance of controllable impedance boards and lines is one of the most important and common problems. First understand the definition of the transmission line: the transmission line consists of two conductors with a certain length, one is used to send a signal, and the other is used to receive signals (remember the concept of "loop" instead of "ground"). In a multi -layer board, each line is part of the transmission line, and the adjacent reference plane can be used as the second line or loop. The key to a "good performance" transmission line is to keep its characteristic impedance constant in the entire line. The key to the "controllable impedance board" is to make the characteristic impedance of all lines satisfy a prescribed value, usually between 25 ohms and 70 ohms. In the multi -layer circuit board, the key to the good transmission line performance is to keep its characteristic impedance constant in the entire line. But what exactl
The testability design of a good product can simplify the preparation of inspection and product final testing in the production process, improve test efficiency, reduce test costs, and easily find the product defects and faults, thereby ensuring the quality stability and reliable quality of the product. sex. 1. Testability of PCB design Like the manufacturing design of PCB, the testability design of PCB also belongs to the processing design of the printed board, which also includes the testability of the printed board manufacturing and finished printing board (light board) Two parts of testability, the test methods and requirements of these two parts are completely different. For the designer of PCB, it is necessary to understand both the performance and testing methods that need to be tested on the printed board, and to understand the installation test requirements and test methods of the printed board assembly parts. With the miniaturization of electronic products, the online
For the design of the chip density and the high clock frequency, the design of the 6 -layer board should be considered. It is recommended to stack the layer: 1. Sig -GND -SIG -PWR -GND -SIG; For this scheme, this superposition layer scheme can get better signal integrity. The impedance of the wiring layer can be better controlled, and both floors can well absorb magnetic lines. And in the case of power and strata, it can provide a good return path for each signal layer. 2. GND -SIG -GND -PWR -SIG -GND; For this solution, this plan is only applicable to the situation where the density density is not very high. This layer has all the advantages of the above layer, and this top and bottom layer The horizon is relatively complete and can be used as a better shield. It should be noted that the power layer should be close to the non -main component surface, because the plane of the bottom layer will be more complete. Therefore, EMI performance is better than the first solution. Summar
For the two -layer board, because the number of plates is small, there is no problem with overlapping layers. Control EMI radiation is mainly considered from wiring and layout; The electromagnetic compatibility of single -layer and double -layer boards is becoming more and more prominent. The main reason for this phenomenon is that the area of the signal circuit is too large, which not only produces strong electromagnetic radiation, but also makes the circuit sensitive to the external interference. To improve the electromagnetic compatibility of the line, the easiest way is to reduce the circuit area of the key signal. Key signals: From the perspective of electromagnetic compatibility, the key signal mainly refers to the signal of strong radiation and a sensitive signal to the outside world. Signals that can generate strong radiation are generally cyclical signals, such as clocks or address low signals. A signal that is sensitive to interference refers to those lower levels of an
1. SIG -GND (PWR) -PWR (GND) -sig; 2. GND -SIG (PWR) -Sig (PWR) -gnd; For the above two layers of stacking design, the potential problem is the thickness of the traditional 1.6mm (62mil) board. The laminar spacing will become very large, which is not only not conducive to controlling impedance, but also inter -layer coupling and shielding; especially the distance between the power supply formation is very large, reducing the board capacitance, which is not conducive to filtering noise. For the first scheme, there are usually many chips on the board. This scheme can get better SI performance, which is not very good for EMI performance. It is mainly controlled by wiring and other details. Main attention: The connected layer of the signal layer with the most dense signal layer is conducive to absorbing and suppressing radiation; increasing the area of the board and reflecting the 20H rules. For the second scheme, the chip density of the board is usually low enough and there is suff
In fact, the four -layer board copy plate is to repeat two double panels, and the sixth floor is to repeat three double panels ... The reason why the multi -layer is daunting is because we cannot see the internal line. How can we see the inner layer of a precise multi -layer board? —— layered. There are many methods on the problem of layered, including potions corroded, knife stripping, etc., but it is easy to divide the layer over the head and lose the information. Experience tells us that sandpaper polishing is the most accurate. When we copy the top layer of the PCB, we usually use sandpaper to polish to grind the surface of the surface to display the inner layer; sandpaper is a common sandpaper sold by the hardware shop. Generally, PCB is paved, then pressing the sandpaper and rubbing on the PCB evenly on the PCB. (If the board is small, you can also lay sandpaper, and press PCB with a finger to rub on the sandpaper). The main point is to pave the flat, so as to grind evenly.
1. Scan the upper and lower surfaces of the circuit board, there are two BMP pictures. 2. Open the copy software QuickPCB2005, click "File" and "Open the bottom diagram" to open a scanning picture. Use Pageup to amplify the screen, see the pad, place a pad in PP, see the line and press PT to walk ... Just like a child drawing, draw it in this software, click "Save" to generate a B2P file. 3. Click the "File" and "Open the bottom diagram" to open another layer of scanning color map; 4. Click the "File" and "Open" to open the B2P file saved in front. We see the just copied board and stacked on this picture -the same PCB board, the hole is in the same position, but the line connection is different from different line connections. Essence Therefore, we according to the "Options" - "layer settings", here to turn off the displayed lines and silk prints, leaving only a multi -layer perforated. 5. The excessive hole on the top layer is in the same position as the perforated on the bott
In simple terms, it is to scan the circuit board to be copied first, record the detailed component location, and then remove the component to make it into a material list (BOM) and arrange the material procurement. Treatment to the PCB board diagram file, and then send the PCB file to the production plate. After the board is made, the purchased components are welded to the PCB board made, and then the circuit board can be tested and debugged. The specific technical steps are as follows: The first step is to get a PCB. First, record the models, parameters, and positions of all components on the paper on the paper. It is best to take a picture of two component positions with a digital camera. Many PCB circuit boards, the more advanced the diodes, the two pole trigelines, are not paid to see. The second step is to remove all devices and remove the tin in the PAD hole. Wash the PCB with alcohol, and then put it in the scanner. When scanning, you need to adjust the pixels of the scan
The PCB copy is a category of reverse engineering. Since the birth of the entire concept, it has been under extensive controversy. The method of reverse engineering has played a huge role in the development of the integrated circuit industry. Methods to understand the development of other people's products. If this behavior is strictly prohibited, it will affect the advancement of integrated circuit technology. Therefore, countries will be regarded as an exception of infringement under certain conditions when legislative. In order to teach, analyze and evaluate the concepts, technology, or the circuit, logical structure, and component configuration used in the design of the cloth design, copy the cloth design and apply the analysis and evaluation results to the original cloth map on this basis In the design, the integrated circuit is made based on this, which is not regarded as infringement. However, it should be considered as infringement, which simply replicate the protection of
Many people have misunderstandings about the concept of PCB copy plate. In fact, with the continuous development and deepening of the copy of the board industry, today’s PCB copy concept has been extended widely, and it is no longer limited to the copy and cloning of simple circuit boards and cloning. It will also involve the second development of the product and the development of new products. For example, through the analysis of existing product technical documents, design ideas, structural characteristics, process technology, etc., you can provide feasibility analysis and competitive reference for the research and development and design of new products, and assist R & D design units to follow up the latest. The technological development trend, timely adjust the improvement of product design plans, and develop the most competitive new products in the market. At the same time, the process of PCB copy plate through the extraction and partial modification of the technical data file
In the 1980s, Western capitalist countries vigorously developed technology, and various high -end technology electronics products came into being. Such electronic products are widely used. Product developers have its full set of technical solutions to monopolize the technical solutions of such products. Some companies developing products have even maliciously raised their products to obtain greater profits. In this monopoly environment, some companies have tried to break this monopoly, gain profits from it, try to imitate such products, and do reverse research and analysis of these high -tech products, which is what we call PCB copy board. The PCB copy industry has also emerged. The concept of PCB copy board was originally born in the 1980s, which was born in reverse engineering in the domestic academic community. After nearly 30 years of development, PCB copy board has become a global global e -industry development and domestic core technology research. In the sexual industry, va
1. Active device, its main feature is: (1) consuming electricity (2). It also needs external power supply. 2. Divided device, divided into (1) bipolar crystal transistor (2) field effect transistor (3) Salonechor (4) semiconductor resistance capacitance 3. The simulation integrated circuit mainly refers to an integrated circuit used to process analog signals by integrated simulation circuits composed of capacitors, resistors, transistors, etc. There are many simulation integrated circuits, such as integrated computing amplifiers, comparators, pairing and index amplifiers, simulation multiplied (except) magic weapons, locking loops, power management chips, etc. The main constituent circuits of the simulated integrated circuit include: amplifier, filter, feedback circuit, reference source circuit, switch capacitor circuit, etc. The design of the simulation integrated circuit is mainly obtained by manual circuit debugging through experienced designers. Most of the digital integrated
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1. Capacitors generally use "C" and numbers in the circuit (such as a capacitor with a number 13 in C13). The capacitor is two pieces of gold Components composed of the membrane are tight and are separated by insulating materials in the middle. The characteristics of capacitors are mainly DC communication. The size of the capacitor capacity is to indicate the size of the energy storage. The obstacle of the capacitor to the communication signal is called the capacity of the capacity. The frequency of flow signal is related to electricity capacity. Rong resistance XC = 1/2πf C (f represents the frequency of the communication signal, C represents the capacitor capacity) The types of capacitors commonly used in the telephone are electrolytic capacitors, porcelain capacitors, patch capacitors, monopolic capacitors, 钽 capacitors and polyester capacitors wait. 2. Recognition method: The recognition method of capacitors is basically the same as the recognition method of resistance, a
The resistance is represented by "R" in the circuit, such as: R1 represents a resistance number 1. The main role of resistance in the circuit is Diversion, current limit, pressure, bias, etc. 1. Parameter recognition: The unit of the resistance is Om (ω), the multiplier unit is: thousands of Euros (KΩ), Mago (MΩ), etc. Convert The method is: 1 trillion Euros = 1000,000 Euros = 1000000 Euros There are three types of parameter marking methods of the resistance, namely the direct marking method, the color standard method and the number of the number. A. The number of bidding methods is mainly used for small -volume circuits such as patch, such as: 472 represents 47 × 100Ω (ie 4.7K); 104 means 100K B. The color ring labeling method is used most most. Four -color ring resistance five -color ring resistance (precision resistance) 2. The relationship between the position and magnification of the resistance of the resistor is shown in the table below: Color valid digital multiplier
Base / thickness: FR-4 / 1.2mm Size: 140mm*159mm Minimum line width / line distance: 6mil / 6mil Minimum Pores: 0.4mm Surface treatment: Electro -plated File format: Gerber Category: Computer; Four Floor Base / thickness: FR-4 / 1.6mm Size: 294mm*200mm Minimum line width / line distance: 5mil / 5mil Minimum Pores: 0.3mm Surface treatment: tin spray (hot wind flat)
Generally speaking, the four -layer circuit board can be divided into top, bottom, and two middle layers. On the top and the bottom layer, the middle layer first uses Add Plane to add internal Plane1 and Internet Plane2 to the most power layer such as VCC and stratum (that is, the corresponding network labels are connected to the corresponding network label with ADD Plane Do not use Add Layer, this will increase the Midplayer, which is mainly used as a multi -layer signal line placement), so that Plnne1 and Plane2 are two layers of copper leather connected to the power VCC and ground GND. If there are multiple power supplies such as VCC2 or strata such as GND2, first use a thick wire or fill the Fill in Plane1 or Plane2 (at this time the bronze skin corresponding to the corresponding copper or the corresponding of Fill does not exist. You can clearly see the wire or obviously see the wire or you can clearly see the wire or the light or the light or Fill) The rough area of the power
Analysis of tin and sulfuric acid before work. Each 100m2 plate is required to add 11L sulfuric acid, 600 g Tin Salt 235, 600 mlsulfotech part A, 800 ml Sulfotech Part B, 750ml STH Additive Sulfolyt. Automatically add 56ml Sulfotech Part A at 200AH. The solution must be conducted every week to observe and adjust the Sulfotech Part A, Sulfotech Part B. The best value of the project SN2+ 20-30 ml/L 24ml/L W (H2SO4) is 98% 160-185ml/L 175ml/L/L Sulfotech Part A) 30-60ml/L 40ml/L) STH (STH Additive Sulfolyt) 30-80ml/L 40ml/L Sulfotech Part B) 15-25ml/L 20ml/L Operating temperature 18-25 ° C 22 ° C Cathode current density 1.3-2.asd 1.7asd [2]
1 process process The printed board of the graphic plate → acid oil removal → scanning water washing → secondary countercurrent water washing → micro -erosion → scanning water washing → secondary countercurrent water washing → copper plating pre -immersing → copper plating → scanning water washing → pre -immersion of tin plating → Tin -plated → III countercurrent water washing → lower panel 2 Detailed process process 2.1 Tin -plated pre -immersion 2.1.1 Composition and operating conditions of tin -plated pre -immersion fluid 2.1.2 The cylinder method of pre -immersing tin -plated groove Add half -cylinder distilled water first, then slowly immerse the 15L mass score of 98%, stir and cool down, add 1.5L Sulfotech Part A, stir well, add distilled water to 300L and stir well to use it. 2.1.3 The maintenance and control of tin -plated pre -immersed groove liquid Each treatment of 100m2 plates requires 1L sulfuric acid and 100mlsulfotech part A. Whenever the slot is treated with
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