This power supply is designed for amateurs, and has been in operation for over 10 years. Its design is very simple and practically immune to RF. It brings together the individual pieces, is the most expensive part of 600VA toroidal transformer, which can be replaced by another with different characteristics, in the case of a voltage between 17 ~ 20V power and right for our needs.
Reference voltage of 7.5 V Zenner diode (6V8 ~ 8V2), shall apply to Q2, which compares the input resistive voltage divider consisting of R5, R6 and VR2, steering Darlington amplifier Q3, which is responsible for driving the output stage, which consists of a driver in Q4 and 4 2N3771 NPN power transistor, which can be mounted directly on the heat sink without insulation, since it is a collector grounded.
The source has a current limit (Q1), adjusted by VR1 and overload LED (DL2) and full protection against short circuits, with zero consumption in case of short circuit can be maintained indefinitely in this state without danger.
(Please note that due to the strong power of the power supply with a casual a short length of cable, high or small section that is strong enough to not exceed the maximum current of 40A. Can not be considered a short circuit and cause the supply of a power supply large amounts of energy).
active rectifier (D1, D2) is recommended for a type of cathode metal screw is on the ground, install a heat sink large enough block. As power transistors using a hedgehog as high as possible, without being isolated as above, can be part of the window of an aluminum frame. We also recommend using mechanical ventilation with the thermostat.
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