The Positive/Negative Power Supply

This Power supply uses the well known LM317 and the LM337 regulators for the variable voltage output. Since the input voltage is only 25.5 volts from a 2 amp xfrmr the voltage is divided exactly in half using two caps of the same value after the AC is rectified. Thus the out put can deliver +(1.2 thru 15) and -(1.2 thru 15) volts relative to common also allowing 2.4 thru 30 volts relative to the positive and negative terminals there. Also on the output is invluded +15 volts (simple 7815 regulator) and -15 volts (7915 regulator). To make the variable supply ver useful a digital LED voltmeter was attached to the chassis. Here is the schematic for the power supply, Enjoy!

And of course the Component list:

TR1 - Stepdown 120v:30V centertaped
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S1-S2 - 120v @ 2 amps
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F1 - 120v @ 750mA
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P1-P2 - Dual potentiometer
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BR1 - 50 volt @ 2 amp (RB151)
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R1-R2 - 2k 1/2w
R3-R4 - 125R 1/4w
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J1-J4 - Banana Jack
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C1-C2 - 6800uF electrolytic caps
C3-C6 - 1-1000uf electrolytic caps
C7-C10 - 1uF tantalum caps
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IC1 - 7815
IC2 - 7915
IC3 - 7805
IC4 - LM317
IC5 - LM337

Dual Supply	AC Filter Side	From the Top	Back	Control Side	Front