How could I make a circuit where whenever a push button is pressed, the output would be a single pulse ? The pulses duration has to always be the same regardless of how long the button is held down. What would be the simplest way of doing this (ideally only using discrete components, so no 555 timers) ?



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    \$\begingroup\$ Why do you want to do this with only discretes? The 555 - or a microcontroller - are ideally suited to this task. \$\endgroup\$ Commented Aug 3, 2015 at 16:16
  • \$\begingroup\$ I agree with Nick-- that's what the 555 is designed to do. Why wouldn't you want to use it? \$\endgroup\$
    – Nevo
    Commented Aug 3, 2015 at 18:05
  • \$\begingroup\$ You're absolutely right, the 555 would be the right way to go. I just need to find the most cost efficient way possible \$\endgroup\$
    – Liam F-A
    Commented Aug 4, 2015 at 0:50

1 Answer 1


This is the simplest way without the 555 timer. You have to play with the RC values and the gate's input should be schmitt triggered.


simulate this circuit – Schematic created using CircuitLab

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    \$\begingroup\$ That just plain won't work. You need, at the very least, pullups on both sides of the cap. \$\endgroup\$
    – EM Fields
    Commented Oct 20, 2015 at 10:28
  • \$\begingroup\$ Good point. I fixed that. \$\endgroup\$
    – Alexxx
    Commented Oct 21, 2015 at 11:40

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