Choosing the right transistor for switching application

Discussion in 'The Projects Forum' started by sonofptolemy, Nov 19, 2012.

  1. sonofptolemy

    Thread Starter New Member

    Nov 10, 2011
    Hi guys,
    I need to create module that can switch between loads.

    There are two input banks, each bank will take about 30V max.
    For each bank I must have TTL outputs for Voltage and current measurements. In the requirements I have specified that there should only be one voltage feedback and one current feedback, and an input switch to switch between banks.

    I have the basic idea in my head.

    But I'm somewhat limited in my experience with Mosfets, BJTs and transistors as switches in general. I've used them for school projects but I never actually selected them I was either given them or my team mates and I would use what was available from scrap electronics etc and looked up their datasheets. I have built robots and such this way. But this time I need to actually do it properly and intentionally.

    Can I get a push in the right direction as to which kind of transistor I should use and how to select it?

    I think I need Power Mosfets, but what kind?
  2. wayneh


    Sep 9, 2010
    Well that's good, but I couldn't make heads or tails of your description. Can you draw out a block diagram of what you want your switch(es) to do?

    You mention using a transistor. Do you not want to use a mechanical switch?
  3. tshuck

    Well-Known Member

    Oct 18, 2012
    ...also, what is your switching frequency?