Alarm circuit

Discussion in 'General Electronics Chat' started by ArlieD, Jun 17, 2009.

  1. ArlieD

    Thread Starter New Member

    Jun 17, 2009
    I am trying to design an alarm circut using the following:

    a N/O circut that closes on alarm this 'trigger' would turn on a relay that would in turn sound the horn. thats easy right? ok Now I need to reset that relay with the trigger still on. That is where I am stuck.

    This is what I have (wish I could draw it out for you)

    AT temp(n/o relay) connects to cr2 (n/c) relay, to turn on cr5 coil.

    cr5 (n/o relay) turns on cr2 to sound horn. I want to reset cr5 with out dropping out at temp.

    Any suggestions??
  2. radiohead

    Distinguished Member

    May 28, 2009
    have the relay coil voltage controlled by a transistor like a D40D8, TIP-series or similar to handle the load.
  3. ArlieD

    Thread Starter New Member

    Jun 17, 2009
    Thank you sir but I decided to use another realay and a reset, once my at temp closes it remains closed , however the horn will only sound untill the reset is pushed at which time I open a contact between the at temp and the horn, I then reset the held in relay at end of cycle to begin again.

    Was staring me in the face, just got a brain freeze I guess.

    Thanks again