Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Switch for AC signal

  1. Apr 10, 2014 #1
    Hi all,

    I would like to make a switch for an AC signal (on off ,ie, high impedance and low impedance). The switch should have less than 1 ohmn impedance. The signal can range from 1-100Khz and the signal will be 50Vrms.

    I tried to use mosfets, but they do not block the signal completely, and I do not think they are meant to control AC signals like this.

    Thanks in advance.
  2. jcsd
  3. Apr 10, 2014 #2


    User Avatar
    Science Advisor
    Gold Member

  4. Apr 10, 2014 #3


    User Avatar

    Staff: Mentor

    You have probably considered simple relays -- could you say why you rejected them? Switching time, bounce, etc?
  5. Apr 11, 2014 #4


    User Avatar
    Science Advisor

    There are many ways of doing it, but it will depend on the maximum signal current.
    Are the signals in a coaxial cable or a twisted pair?

    Often a “T” structure switch is used. Two series switches in the top of the “T” are used to block the signal while another switch in the stem of the “T” grounds the midpoint when the switch is off to greatly reduce feedthrough. Perhaps you can use that structure with mosfets.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook