Constant to momentary trigger circuit

Discussion in 'The Projects Forum' started by Javi, Jan 13, 2009.

  1. Javi

    Thread Starter New Member

    Jan 11, 2009

    I have to build a triggering circuit for controlling a transmitter that requires a momentary connection to the 6V Vcc line. (I believe that the input is a BJT and therefore requires a small amount of current to be supplied to it.) The only control signal I have available to me for controlling the transmitter is a switch that goes from "no connect" to 6V and stays there while a person is detected in a room. At the end of the day, I need to use the rising edge or the 6V level at the control signal to generate a momentary pulse that lasts for about a second and then goes back down to no connect until the process is repeated again.

    Any ideas?
    I appreciate any help I can get.
  2. mik3

    Senior Member

    Feb 4, 2008
    How this switch is activated?
    You mean that you want to reset the switch at some time in the day and make it from close to open?
  3. Javi

    Thread Starter New Member

    Jan 11, 2009
    Thanks for your reply. Actually, I found that I don't need to build a circuit at all. I got the answer to my problem by discovering the existence of "time delay relays". They do exactly what I want when I want. Thanks again!