Benchtop power supply with 9v and 1.5 volt outputs

Discussion in 'The Projects Forum' started by truwebs, Apr 15, 2016.

  1. truwebs

    Thread Starter Member

    Apr 2, 2016
    I am buidling a benchtop power supply from an ATX power supply. I understand using the color codes how to accomplish 12v, 5v, and 3.3v connection connection ports.

    How could I add 2 more power ports for 9v and 1.5 volt?

    Basically I am trying to minimize the use of batteries in my testing with most common power sources. Any other options I should consider

    I have read a little about the -12v and -5v being obsolete power options. Is there any need for these voltage outputs for a newbie electronics hobbiest?


  2. #12


    Nov 30, 2010
    LM317 and or LM7809
    I use -12v or -15v for audio amplifier op-amps.
  3. dannyf

    Well-Known Member

    Sep 13, 2015
    There are 9v reglators: LM7809 or its clones. And I'm sure that there are 1.5v regulators too but they are rare.

    In any event, you can simply take a regular adjustable regulators, and put two resistors to them to make them 9v/1.5v regulators. The calculation is trivial and always laid out in the datasheet of the devices you do use. Just make sure that their feedback voltage is less than 1.5v - they are generally the case.
  4. Dodgydave

    Distinguished Member

    Jun 22, 2012
    Use lm317/338 regulator to give your 1.5 v
  5. crutschow


    Mar 14, 2008
    A #12 noted, minus voltages are often used for audio op-amps, since a normal ground-referenced AC audio signal goes above and below ground.
    If you use only one supply for a audio amp then the audio needs to be DC offset so that the signal never goes below ground, and that requires additional parts.