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    Help needed on Simple Timer Issue - Timer not correct due to Caps not discharged

    All,

    please help me on the below.

    I'm using simple timer 2.5 seconds using Transistor and Caps.

    As Caps discharged takes more time via bleeder resistance, the timer is incorrect on successive tries.

    how can I momentarily short the caps and discharge either after switch of main voltage supply or during power on.

    the circuit I try is very basic as in the link http://homemadecircuitsandschematics...explained.html


    please help me and advice any change of or new circuit

    thanks in advance.

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  2. #2
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    Re: Help needed on Simple Timer Issue - Timer not correct due to Caps not discharged

    That method isn't particularly reliable but keeping it simple, the easiest solution is to use a change-over switch instead of a press-to-make push button. Wire it so that when the button is released you connect a low value resistor (~47 Ohms) across the capacitor to give it a higher discharge current. Do not simply short the capacitor out as the spark will damage the switch contacts.

    Brian.
    PLEASE - no friends requests or private emails, I simply don't have time to reply to them all.
    It's better to share your questions and answers on Edaboard so we can all benefit from each others experiences.



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