High Current Power Supply

Since my page was first posted, I have received a number of emails asking about a high current power supply. I looked around, but couldn't find one that was suitable. So, I designed this. It is a linear supply, which might have a few of you rolling your eyes, but it takes very few parts, is simple to build and can supply huge currents.

Schematic

Parts

Part Total Qty. Description Substitutions R1 1 680 Ohm 1/4 Watt Resistor C1 1 20,000 - 50,000uF 20-40 Volt Capacitor C2, C3 2 100uF 50 Volt Capacitor C4 1 0.1uF 50 Volt Capacitor C5 1 0.01uF 50 Volt Capacitor D1 1 Zener Diode (See Notes) Q1 1 2N3055 Or Other (See Notes) T1 1 Transformer (See Notes) BR1 1 Bridge Rectifier (See Notes) S1 1 SPST 250 VAC 10 A Switch MISC 1 Case, Line Cord, Heatsink For Q1, Binding Posts For Output

Notes

1. D1 should be rated at about one volt higher than then desired output of the supply. A half watt diode will do.
2. Q1 can be a transistor similar to the 2N3055. I chose the 2N3055 for it's availability and power handling (150 watts).
3. T1 should be about 5 volts higher than the desired output of the supply, and rated for about one amp more of current. The voltage overhead is required by the regulator section. The extra current is to keep the transformer from over heating.
The choice of BR1 will depend on the voltage and current of your transformer. The rectifier should be rated for 50 volts more than the transformer, and 5 amps more than the transformer.
4. The value of R1 will be smaller when supplying high currents. Expiriment until you get what you need.
5. You are going to need to heatsink Q1 and BR1. Use a small PC case style fan unless you are going to run large heatsinks.