Time delay on, delay off?

Discussion in 'General Electronics Chat' started by MRW1962, Jun 29, 2012.

  1. MRW1962

    Thread Starter New Member

    Jun 29, 2012
    18
    0
    I am constructing a detector circuit that will sense 18vac that is sometimes intermittent or "bouncy" at first. Because of this bounce, by circuit output chatters alot due to the fact that the control for the output is a sensitive relay (12V, 720ohm coil).
    What I want to do is have some kind of circuit that will have an ON delay of .5 second, and an OFF delay of 1.5 second.
    My thoughts are to use a 555 timer and a capacitor/resistor setup to drive my relay directly, or drive a 4066 switch. I just need a little direction towards proven simple designs.
    - Miles
     
  2. MRW1962

    Thread Starter New Member

    Jun 29, 2012
    18
    0
    Here's a little more info on this circuit:
    It outputs 12V to a 12V, 720 ohm relay when it senses 18VAC. Problem is that the output has alot of bounce due to intermittent contact at the 18VAC side for about .5 second. My timer circuit could be of the type to turn on immediately, but then turn off after a period of inactivity maybe a second or two, this would eliminate any bounce in the output I think. So instant ON, and delayed OFF is what I really need. I am currently browsing the 555 threads, but if you have a pointer let me know.
    - Miles
     
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