power supply delayed signal

Discussion in 'General Electronics Chat' started by Sibithomas, Nov 9, 2011.

  1. Sibithomas

    Thread Starter New Member

    Oct 27, 2011
    6
    0
    Hi All,

    I just want get two edge signals from 'power on signal' (please see the attachment). One edge should have a delay of 200 ms and second edge should have a delay of 400 ms.

    For generating these two edges, can I use simple RC circuit ORed together as shown in the attachment?

    Do you have any other good idea istead of this one?

    Please help !!!!

    Thanking you in advance
    Sibithomas
     
  2. elec_mech

    Senior Member

    Nov 12, 2008
    1,513
    193
    Hmm, what are you trying to do with this? Your signal diagram shows two outputs, 1 and 2, but your schematic shows one output only.

    The RC portion looks okay to me, but if you tie the outputs together as shown, the output will go high and stay high in 200ms. In other words, the second output will serve no purpose.

    You can also use a 555 in monostable mode to get the desired time delay - one 555 per output. More info here: http://www.kpsec.freeuk.com/555timer.htm#monostable.
     
  3. Sibithomas

    Thread Starter New Member

    Oct 27, 2011
    6
    0
    Thank u elec_mech!!!!

    U r right. It is a mistake...

    What about the circuit with two outputs....??? ie same circuit without the Oring and diodes.

    Will it work?

    Thanking you in advance!!
    Sibi
     
  4. elec_mech

    Senior Member

    Nov 12, 2008
    1,513
    193
    I should. If you have an o-scope, you can try it and check it before hooking it up to your input circuit.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Here, this should pretty much do it for you.

    See the attached.

    You may need to adjust R1 and R2 somewhat, as capacitors have a fair bit of tolerance - and so do the thresholds of Schmitt trigger inputs of IC's made by various manufacturers. This is just a good starting place.

    You didn't say which edge, so this circuit outputs two falling edges; one at 200mS and one at 400mS.
     
    Last edited: Nov 9, 2011
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