a simple question

Discussion in 'General Electronics Chat' started by simf14, Feb 6, 2009.

  1. simf14

    Thread Starter Active Member

    Jul 27, 2007
    From a novice:

    I have four, 4-amp, 12V devices I need to power at the same time. Do I use a 4 amp 12V transformer, or is it 16 amps?

    Thank you for helping.

    Curtis P.
  2. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
    Yer gonna need 16A

  3. Torben

    New Member

    Mar 15, 2008
    Hi there,

    Note that I'm just some guy with a soldering iron and a workshop, not an electrician or EE. But I honestly think that to get a usable and safe answer you need to provide more information. For instance:

    Are the 4 devices 12VAC or 12VDC? In series or parallel? Are there motors, large caps, etc involved?

    If they're arranged in series you could use (on paper) a 48V 4A transformer; in parallel you'd need at least a 16A transformer. Although I think it would be a better idea to use a somewhat larger transformer than you think you'll need, especially if these "devices" have any kind of inrush current surge when first energized. Motors, large capacitors, etc. can all cause larger than normal current drains during first few moments of life.

    I think more information is needed to answer this properly.


  4. simf14

    Thread Starter Active Member

    Jul 27, 2007
    Wow thank you for the help. They are solenoids for hydraulic actuator valves on a flight simulator, 12VDC hooked up in parallel, no caps or other things involved. Hooked them up to a 12VDC, 2A car battery charger in parallel and they just work. The 4A, 12V is stamped on them and is probably the max rating. The specs are here...http://www.hydraforce.com/Electro/Elec-pdf/3-200-1.pdf Part #6306012. (at 14W, they are 9.8 ohms with initial amp draw 1.22)