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.
Circuit is very good but how can I adjust power
Hello Prajwal
In the trimpot.
This is working link of this post: https://docs.google.com/file/d/0B5uAoDP4k0RPZGd6MGJBMlg4bG8/edit?usp=sharing
Hi, do you have the PDF file? The file is not longer available on 4shared.
Thanks!