Connect with us

simple circuit help

Discussion in 'General Electronics Discussion' started by paul60, Mar 30, 2015.

Scroll to continue with content
  1. paul60


    Dec 11, 2010
    I have fitted a reed switch to a piece of equipment this is kept activated by a magnet. if there is a problem the reed switch will open.
    when the reed switch open i want a 120v supply to an alarm also a manual switch to break the circuit when the alarm goes off.
    can a solid state relay be used for this.
    Seen a few on Ebay at some very good prices.
    thanks Woodguy
    need help inn making a circuit for the above.
  2. Harald Kapp

    Harald Kapp Moderator Moderator

    Nov 17, 2011
    You can use any relay as long as:
    1. the parameters on the coil side (voltage, current) match what is available in tems of low voltage power supply and reed switch capability.
    2. the parameters on the contact side (voltage, amperage or wattage) match the requirements of the high voltage load.
    A simple circuit setup looks like this:

    The low voltage side (V1) is powered by a safe power source, e.g. a 12V power supply (or a 5V wall wart or whatever you have).
    The reed contact is normally open, the manual breaker /switch) is normally closed.
    When the reed contact is closed, the coil of the relay is powered and the relay is actuated. Note that I have drawn a conventional relay but a solid state relay will work as well provided the parameters of the input side atch the power supply you have.

    When the relay is activated, the mains circuit is closed and the buzzer (or whatever load you use) is turned on. If you actuate the manual breaker, the primary side of the relay is without power and the relay contact on the secondary side opens, turning off e.g. the alarm.

    Attached Files:

  3. paul60


    Dec 11, 2010
    Harald thanks for taking the time to help
    all the best .Paul
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day