How to reverse polarity on a Peltier heater/cooler

Discussion in 'The Projects Forum' started by Ramjet33, Feb 26, 2015.

  1. Ramjet33

    Thread Starter New Member

    Feb 25, 2015
    1
    0
    The project is to make a constant temperature cabinet. A good commercial example is the Memmert ISP260.
    I propose to use Arduino, an old PC power supply, and two heat sink/fan assemblies that sandwich a Peltier cooler.
    How can I use the arduino to switch polarity on the Peltier so one device can be used to provide heat or cooling as required?
    I'm an old programmer and just aquired electronics for this project. I believe I have the programming nailed but how and what to use with the ardrino to switch polarity on the Peltier has me currently stumped.
    Hope someone can shine a light.
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Last edited: Feb 26, 2015
  3. wayneh

    Expert

    Sep 9, 2010
    12,145
    3,055
    There's your answer. Use a lightbulb as a heat source and design the peltier to only cool. Much simpler.
     
  4. crutschow

    Expert

    Mar 14, 2008
    13,025
    3,236
    If you wanted to do it with all electronics you could use a MOSFET bridge circuit, but a relay is simpler and has a lower voltage drop.
     
  5. wayneh

    Expert

    Sep 9, 2010
    12,145
    3,055
    Don't forget to include an "off" position, where it is neither heating nor cooling.
     
  6. MrChips

    Moderator

    Oct 2, 2009
    12,447
    3,363
    Use an H-bridge.
     
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