Adjustable Symmetrical Power Supply With LM317 and LM337

The circuit will serve as a voltage converter with an input voltage of 35 V to produce an output voltage of 1.25 V to 30 V. The positive voltage is being handled by LM317 IC while the negative voltage is handled by LM337. The circuit can provide an output current of 1 A. During the production of 1 A current, the regulator is dissipating too much heat and without the presence of a heatsink, the regulator may get damaged.

The adjustable symmetrical power supply is suitable to be used in audio amplifiers, microphone amplifiers, op-amp applications, impedance converters and other devices that require regulated positive and negative DC supply, since the output current is 1.5 A.

Schematic  Symmetrical Power Supply Using negative and positive Regulator IC’s LM317 and LM337

Pcb for Symmetrical Power Supply Using negative and positive Regulator IC’s LM317 and LM337

Part List for Symmetrical Power Supply Using negative and positive Regulator IC’s LM317 and LM337

Part	Value
Resistors 1/4 Watt 5%
R1, R2	220 – Red, Red, Brown, Gold
Capacitors
C1,C2	4700µF/50 V – Electrolytic Capacitor
C3, C4, C7,C8	100nF/100V – Polyester or ceramic capacitor
C5,C6, C9,C10	10µF/50V – Electrolytic Capacitor
Semiconductors
D1, D2, D3, D4	1N4004 or equivalent – Diode Rectifier
IC1	LM317T – Positive Adjustable Voltage Regulator
IC2	LM337T – Adjustable Negative Voltage Regulator
Connectors
CN1	Connector for transformer
CN2	Connector regulated output voltage
Miscellaneous
P1, P2	4.7K – Trimpot horizontal assembly
Transformer 12 to 22 Volts with center tap and current according to the need to 1.5A max
Welding, Wire, box to accommodate circuit, printed circuit board, heat sink for ICs, etc..

Download the PDF for this assembly: Printed circuit board, schematic, component layout, component Silkscreen, LM317 Datasheet, LM337 Datasheet, AN-181 lm317 adjustable regulators.

Download PDF    Mirror