Timer

Discussion in 'General Electronics Chat' started by fahimraja, Sep 14, 2012.

  1. fahimraja

    Thread Starter New Member

    Sep 12, 2012
    6
    0
    I AM JUST DESIGNING A TIMER CIRUIT...
    ON TIME=10μs
    OFF TIME=1ms

    ToN=0.69(R1+R2)*C
    ToFF=0.69(R2)*C

    PLZ HELP TO DECIDE TO PROPER VALUE OF R1,R2,C

    I am waiting for your response..

    Thanks
    Mohammad Fahim Raja
     
    Last edited by a moderator: Sep 14, 2012
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,985
    745
    try a10nF cap and a 145K resistor for the 1mSec, then use a 1.5K resistor for the 10uSec, if you use the hysterical osc circuit configuration, that uses pin 3 as the capacitor supply, you will need to put in two diodes in series with your resistors, one in each direction.

    http://www.allaboutcircuits.com/vol_6/chpt_8/3.html
     
    Last edited: Sep 14, 2012
  3. fahimraja

    Thread Starter New Member

    Sep 12, 2012
    6
    0
    well..dear....u said right...thanx alot....
     
Loading...