Powering Multiple Kits from Wall Wart

Discussion in 'General Electronics Chat' started by imruffsdad, Nov 11, 2012.

  1. imruffsdad

    Thread Starter Member

    Jul 18, 2008

    I've read through some threads here and I'm hoping to summarize what I want to do and see if I understand it correctly. I have built several little electronics kits (wheel of fortune, blinky, sound generator, etc.) for this first question let's assume they all run on there own 9 Volt battery.

    Yes or No (or it ain't that simple)
    Can I use a single 9 Volt wall wart to power all of these kits as long as I don't exceed the total combined amperage of the devices?

    Question 2, let's assume for this one that 3 of the kits use a 9 volt battery and 3 of them use 3 volts.

    I'm assuming that I can wire up the 3 9 volt ones directly. How do I step down the 9 volt Wall Wart to power the 3 volt kits?

    In my head I'm thinking I take a 9 volt lead from the wall wart and hook it to some type of step down circuit and then run the 3 volt leads off of that circuit. Again I'm thinking as many 3 volts as I want as long as all kits (3 & 9 volts) don't exceed total amps of the Wall Wart.

    Really appreciate your help on this. My ultimate goal is to build a panel of 8 - 10 of these kits powered off a Wall Wart so I can power any one or all of them without having to deal with battery replacements.

    Thanks a bunch,

  2. KJ6EAD

    Senior Member

    Apr 30, 2011
    Yes. I made a supply bus with multiple battery snaps along a length of split loom tubing for a display once. Many of the kits that use a 9V battery can be safely run from 12V as well.

    The simplest way is to set up an LM317 adjustable voltage regulator to provide the 3V. If you're not drawing too much current, you won't even need a heat sink.
    imruffsdad likes this.
  3. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    Just so its clear.. You buy a 9V wall wart that has a current rating "greater" than the total of all the devices.. Loads (your devices) only "pull" what they require. I usually go 125% or more. So if your devices require 3 Amps get a wallwart with a rating of 4 Amps or more.
    imruffsdad likes this.