fast switch on - Slow Switch Off

Discussion in 'General Electronics Chat' started by ptaylor, Apr 9, 2014.

  1. ptaylor

    Thread Starter New Member

    Sep 23, 2009
    3
    0
    I need to make a voltage level decay slowly (approx 2 sec)when switched off, i need it to come on fast on start up, any circuit ideas or suggestion appreciated.

    Kind regards
    Paul
     
  2. #12

    Expert

    Nov 30, 2010
    16,257
    6,762
    Adjust the resistor and capacitor to achieve the correct output voltage at 2 seconds after turn off.
     
  3. wayneh

    Expert

    Sep 9, 2010
    12,094
    3,033
    Note that the resistor in your circuit may just be your load, and you just need to find a capacitor large enough to power your load for 2 seconds. Easy if you know how much it's drawing.

    What are you trying to do?
     
  4. ptaylor

    Thread Starter New Member

    Sep 23, 2009
    3
    0
    Thanks #12 and wayneh just what I needed.


    Paul
     
  5. ptaylor

    Thread Starter New Member

    Sep 23, 2009
    3
    0
    Is it the normal time constant formula T = R X C
     
  6. #12

    Expert

    Nov 30, 2010
    16,257
    6,762
Loading...