Ron Broberg/Projects/Variable Voltage Regulator

This variable voltage supply is built on the | LM317 variable voltage regulator integrated circuit. It is based on one by |Tony van Roon. The left hand circuit in TvR's original can be replaced with an ATX computer power supply. The right hand circuit in TvR's original was replaced by a handheld voltmeter. This variable voltage regulator supplies 1.2VDC - 32VDC at about 1.5 amps.

=Photographs=









=Bill of materials=

Power supply (in)
 * BR1 = Bridge Rectifier
 * TR1 = Transformer 24VAC, 3A
 * S1 = On-Off toggle switch
 * Fuse = 115V, 500mA, slow-blow
 * FuseHolder, enclosure, knob for P1
 * Plug = 3-wire plug &amp; cord

Voltage Regulator
 * IC1 = LM317, adjustable regulator
 * D1 = 1N4001
 * C1 = 1000uF/63V, electrolytic (see text)
 * C2 = 0.1uF (100nF), ceramic
 * C3 = 1uF/40V, electrolytic
 * R1 = 22K (18K in orig)
 * R2 = 220 ohm
 * R3 = 27K
 * Led1 = Led of your choice
 * P1 = 5K, potentiometer
 * Red and Black Banana Jacks, coolrib for IC1.

Voltmeter (Not used)
 * V = Meter, 30V, Ri = 85 ohm
 * P2 = 10K, Bourns trim-pot