Dual Adjustable Power Supply

  • Rajkumar Sharma
  • 31650
    Views
  • medium
  • Tested

004_PIC

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

Description

The circuit is based on LM317 positive and LM337 negative voltage regulators. LM317 series of adjustable 3 terminal regulator is capable of supplying in excess of 1.5A over a  1.2V to 30V DC output range, due to TO3 package of  IC and large heat sink the power supply can handle maximum load  current.

  • Output: +/- 1.2 to 30V DC
  • Output Current: 1.5Amps
  • Supply Input: 24V-0-24V AC, 2Amps Center tape Transformer
  • CN1: Transformer Connections
  • CN3: +/- Dual Supply Outputs
  • P1: Positive Voltage Adjust
  • P2: Negative Voltage Adjust
  • D1: Positive Power Indicator
  • D2: Negative Power Indicator

Schematic

004_Schematic

Parts List

004_BOM

PCB

Downloads

Comments

  • Benjie

    can the transformer be replaced with a higher current rating like 3 or 5 amps?

    3 years ago
  • Electronics Lab

    Sure, it will not be a problem to use a higher rating transformer if the voltage is still 24V

    3 years ago
  • brirky

    Can I use this two 220VAC/12VAC halogen transformer serial connected?
    http://www.ebay.es/itm/201209984483?_trksid=p2060353.m1438.l2649&var=500403606005&ssPageName=STRK%3AMEBIDX%3AIT
    If they have 12VAC 60W output each, I should get 24VAC 120W 5A output.
    Or this one :
    http://www.ebay.es/itm/361038813028?_trksid=p2060353.m1438.l2649&var=630376295270&ssPageName=STRK%3AMEBIDX%3AIT
    Connected directly to the output of the diode bridge.
    Which one is the best option?
    Thanks

    3 years ago
  • Demetrio M. Olarte

    How can I make the output voltage be 0-30 volts?

    3 years ago
  • saranya

    thankyou

    3 years ago
  • Shivenarayan yadav

    Very good work

    3 years ago
  • Romar

    what would be the output voltage range if i only used a 15 – 0 – 15 transformer? thank you. great work by the way, neat and nice.

    3 years ago
    • Electronics Lab

      With a 15Vac transformer you will get around 21V peak voltage, minus the voltage drop in rectifier and regulator you will get around 16-17V at the output.

      3 years ago
  • Jommy

    Please I need to implement this as a 12V, 2A dual output unit what modifications do I need to make.

    3 years ago
    • Electronics Lab

      LM317 can go up to 2.2A, so you can try with a bigger transformer to get that current output.

      3 years ago
  • Riza

    why not LM317T or LM337T ?

    3 years ago
  • Ritesh

    I used 24-0-24V, 1Amp Transformer as i needed max 1 Amp. The problem with the circuit is, without any load connected o/p is 1.5V to ~33V at positive side and the same with negative side ( obviously with -ve values). (after measuring on multi-meter) But, as i connect any load the +ve side provides stable and proper voltage supply. However, on -ve side it just stuck around 1.5V to 3V. I checked for any short circuits, bypass capacitors, etc. And every thing is seems good. But, only at pin’s of LM337 might be problem . so, i tried with LM905 and the same thing happens with it. no voltage at output when load is connected.
    Please, let me know what’s happening? and how to make corrections?
    Thanks in Advance…

    1 year ago
    • admin

      What load do you connect? How much current it draws?

      1 year ago
  • tianqiu

    What is 220E?

    1 year ago
    • admin

      It’s 220 Ohm

      1 year ago
      • tianqiu

        Can i change the bridge rectifier into 4 silicon diode (1N4007)?

        1 year ago
        • admin

          No, you will need diodes that can withstand higher currents, at least 3A to be on the safe side.

          1 year ago
  • SARATH SIVADAS

    please add pcb layout in pdf format

    8 months ago
    • admin

      PCB in PDF is attached above. Thanks

      8 months ago
  • Yhan

    why the starting voltage is 1.2v ? how can i get 0 volts in the start ?

    6 hours ago

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