Power is not like a processor, you can see the specifications and performance; power is not like a graphics card, a key GPU to determine the grade. In addition to meeting the power requirements, a good power supply must also consider factors such as stability, energy saving, quietness, and security. In the absence of professional equipment for testing, we only know the basic principles and component knowledge of some power supplies, so that we can "see at a glance" the power supply. From the outside, it seems that the power supply is a little bigger than a "brick", but it has a lot of things in the "belly". Unpacking the case, we can see hundreds of different kinds of electronic components and complex interlaced cables, which can be dazzling. As the saying goes, "The thief first smashes the king." When observing the power supply, we should also pay attention to the following parts. The internal structure diagram of a power supply, numbers 1 to 6 respectively identify the parts that should be emphasized. 1. First and second level EMI filter circuit. The function of this part is to filter the commercial power entering the external power grid and obtain relatively pure AC power for subsequent use. 2. PFC circuit. Its function is to reduce harmonics in the process of converting AC power into DC power, reduce interference to indoor power grid and utility power grid, and reduce utility power loss. 3. High voltage filter capacitor. Its role is to purify high-voltage direct current, providing relatively "pure" current for subsequent high and low voltage conversion. 4. Power topology. Topology refers to the overall structure of the power supply, which directly affects the conversion efficiency of the power supply. 5. Inductor coil of low voltage filter circuit. Its role is to stabilize the voltage and current at the output, which is directly related to the stable use of the computer hardware system. 6. Heat sink. When the voltage is converted by the transformer and the switching circuit, a large amount of heat is generated, so the heat sink is required to rapidly transfer heat. National 3C certification mandatory power supply must be certified by EMI to prevent electromagnetic radiation, so qualified power supplies should have EMI filter circuits. The first-stage EMI filter circuit is located at the power interface, and the better-working circuit also has a separate PCB board and an inductor coil. The secondary EMI filter circuit is usually composed of components such as an inductor coil and a capacitor on the main PCB of the power supply. PFC circuits are divided into passive and active, and most power supplies are now active PFC. Passive PFCs use this "big head" inductor Inductive coils of active PFCs are often located in front of high voltage filter capacitors The power factor of passive PFC is generally around 0.7, and the power factor of active PFC is as high as 0.9 or more, which is obviously better than passive PFC. The resolution of the two is also quite easy. Which are high voltage filter capacitors? Very simple, the highest and largest capacitors in the power supply are (1 to 2). When comparing capacitors, in principle, they can only be compared with the same type of power supply, because at the same power, the passive PFC power supply requires more capacitance than the active one. When comparing at the same level, we can see the capacity, withstand voltage and temperature resistance of the high-voltage filter capacitor. In theory, the larger the three values, the better. The power supply uses active PFC, so a high-voltage filter capacitor with a capacity of 330μF can be used. The capacitor has a withstand voltage of 400V and a temperature resistance of 85°C. To put it simply, in the past few years, the topology of the power supply can be divided into two types: the half bridge type and the forward type. The half-bridge type is a traditional power supply structure, and the conversion efficiency is usually not high; and the forward structure conversion efficiency is easy to achieve more than 80%. Traditional half-bridge topology Forward topology helps improve conversion efficiency In the resolution, we may wish to use the exclusion method: in the center of the half-bridge power supply, there must be three transformers, and one or two small, arranged in a straight line; if your power supply is not this structure, then congratulations, this is mostly It is a forward power supply. Inductor coil of low voltage filter circuit In the low-voltage filter circuit part, we mainly look at the size, number of turns and color of the inductor. Naturally, the larger the coil, the more the number of turns, the better; as for the color, the theoretically superior to the poor are gray, black, light green and yellow, respectively, the better the inductance, the smaller the loss. The low-voltage filter circuit part mainly depends on the inductor coil Single point load cells are a type of weight sensor, also know as parallel beam Load Cell, It will offer high accuracy and high reliability, they are widely used in small bench scales,platform scales, medical scales, light capacity filling machines packaging machines and other weighing devices. Single Point Load Cell,high accuracy load cell,High Precision Load Cell,Load Cell Meter,Planer beam load cell GALOCE (XI'AN) M&C TECHNOLOGY CO., LTD. , https://www.galoce-meas.com
