Whether the computer or electronic maintenance production cannot do without power supply, the power supply of a DC voltage from 3V to 15V continuously adjustable, the maximum current up to 10A, the circuit with temperature compensation characteristics, the standard voltage source with high precision integrated circuit TL431, the voltage stabilizing accuracy higher, if there is no special to meet the basic requirements, the maintenance of normal use, the circuit shown below.
As shown in Figure 1 shows a large power adjustable regulated power supply circuit
High power adjustable regulated power supply circuit
Figure 1 power adjustable regulated power supply circuit
Its working principle is divided into two parts. The first part is a fixed 5V1.5A voltage stabilized power supply circuit. The second part is another route 3 to 15V continuously adjustable high precision high current voltage stabilizing circuit. The first circuit is very simple, the DC voltage through the silicon bridge QL1 rectifier by transformer secondary 8V AC voltage by C1 electrolytic capacitor filter, then the 5V three terminal regulator LM7805 without any adjustment can produce 5V1A regulated power supply is fixed at the output end of the power supply, repair the computer board in the examination can be used as the internal power supply. The second part of the ordinary stabilized power supply is basically the same, the difference is used with temperature compensation characteristics, the standard voltage source with high precision integrated circuit TL431, so the circuit is simplified, the cost is reduced, and the voltage regulation performance is very high. In resistance R4, TL431 regulator, potentiometer R3 to form a continuous adjustable voltage source, to provide the reference voltage for the BG2 base TL431 regulator voltage value can be adjusted continuously, the voltage value determines the maximum output voltage of the power supply, if you want to expand the scope of adjustable voltage, resistance to change the R4 and R3 values, of course, the secondary voltage transformer to improve. The power of the transformer can be mastered flexibly according to the output current, and the secondary voltage is about 15V. Bridge rectifier with 15 - 20A silicon bridge rectifier, the structure is compact, the middle of a fixed screw, can be directly fixed in the housing of the aluminum plate, QL. The adjustment work is high current NPN type metal shell silicon tube, due to its large quantity of heat, if the case allowed, try to buy large fins, enlarges the radiating area, if you do not need a large current, also can be used for the power of smaller silicon tube, so you can do some small volume. Only three were used for parallel filtering 50V4700uF electrolytic capacitors C5 and C7, the output current is more stable, in addition to the capacitor to buy a relatively large volume point, the smaller the same mark 50V4700uF as much as possible, when the voltage fluctuates frequently, or not in a long time, easy to failure. The final say on the power transformer, if not their ability to have around the system, not buy ready-made, can buy more than one off the 200W switching power supply instead of transformer, so the voltage regulation performance can be further improved, the production cost is not too bad, other electronic components without special requirements, after the completion of the installation without much adjustment you can work normally.
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