Dual Adjustable Power Supply Circuit

This is the circuit diagram of a dual adjustable power supply using IC’s LM 317 & LM 337.LM 317 is able to deliver a maximum of 1.5 A at a range of 1.2 V to +30V .LM 337 is the negative complement of LM317.They also have a built in short circuit protection.

Here the circuit is wired to produce a dual adjustable output of ( +15 , 0 , -15 ).The capacitors C1 to C8 provides filtering and ripple rejection.Resistors R1 & R2 controls output of LM 317.Resistors R3 & R4 controls the output of LM 337 .R1 and R4 can be turned to vary the positive and negative voltages.This circuit is a must on an electronic hobbyists workbench.

Circuit Diagram :-

List of Components :-

C1, C2 2200 uF 50V Electrolytic Capacitor
C3, C4, C5, C7 2.2 uF 50V Electrolytic Capacitor
C6, C8 100 uF 50V Electrolytic Capacitor
R1, R4 5K Potentiometer
R2, R3 220 Ohms 1/4 W Resistor
D1 to D4 IN 4007 Diodes
U1 LM317 U2 LM337 T1 24 0 24 Center Tapped 2 Ampere Transformer
S1 SPST 2 Ampere Switch
Extra Heat sinks for two IC’s , Power Cord, Casing, Wire etc

 Important NOTE :

1. The transformer should be anything that produces a min of 3 A with (24 0 24 ) output voltage.
2. The voltage range can be further increased by increasing transformer output within the limits of IC.
3. Do not connect a load drawing more than 2A at output.The IC,s must be fitted with heat sinks for better protection.