+/-12V Dual Power Supply

Rajkumar Sharma      http://www.rajkumarsharma.com  
Project tested


This project is a solution to power up most of devices or projects requiring dual (+/-12V) power supply.


Symmetric +/-12 VDC power supply has been designed for audio applications, can power up microphone pre-amplifier, audio buffers, audio mixer, distributions amplifier, headphone amplifier, VU meter and few o other equipment or projects required dual supply.


  • Mains supply input 240 VAC
  • Step Down Transformer 15-0-15V AC @ 350mA.
  • Output +/- 12 VDC Dual, 350 mA
  • Regulated Low ripple DC output
  • Earth connection for chassis ground
  • Onboard regulator for stable supply
  • Dual output LED indication
  • Supply input & output via screw terminal connector
  • Dual unregulated output +/- 22 VDC via berg connector







21 Response on “+/-12V Dual Power Supply

  1. I want to buy a +- 15 volt dual power supply or +-20 volt dual power supply, for project work.
    can you help please?

  2. HI, adrianhuidobro

    This power supply will work perfectly with 24V (12-0-12) Transformer, and it will provide +/-12V DC.

    This project has bridge rectifier and usually during each half cycle the current flows through two diodes instead of just one so the amplitude of the output voltage is two voltage drops ( 2 x 0.7 = 1.4V ) less than the input VMAX amplitude. The ripple frequency is now twice the supply frequency (e.g. 100Hz for a 50Hz supply. Peak V is theoretically ~1.414 times the RMS voltage. So if you use 12-012 Transformer output would be 12X1.4= +/-16.8V DC Approx. 7812 and 7912 regulate the voltage and provides +/-12V DC.

  3. Rishabh Upadhyay,

    If you wish to use this power supply for different voltages,
    You will have to change the regulator Part no & Transformer voltages as per bellow details
    For +/-5V DC Output
    Regulator LM7805 & LM7905 and AC transformer 5-0-5 V AC to 12-012 VAC

    For +/-15V DC Output
    Regulator LM7815 & LM7915 and AC transformer 18-0-18 VAC

    For +/-18V DC Output
    Regulator LM7818 & LM7918 and AC transformer 24-0-24 VAC

  4. How can i get 4 amperes with this power supply, as the ics are rated at 1amp Max i cant get a transformer which is more than that, so i need more amperes

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