I was wondering if there is a simple 555 Timer circuit, or even simple transistors circuit, that has a HIGH output for 1sec, 2sec, or more seconds when I trigger the input switch and will remain HIGH till the specific time is done then it will go LOW. Knowing that when I trigger the input switch like 5 times quickly and repeatedly this shouldn't impact/interrupt the output at all, which means when I hit the input switch a multiple times the output will go HIGH for 3 seconds or whatever the time and will turn off once time cycle is done, and will go HIGH again for another 3 seconds if I'm still hitting the switch!

Sample timing diagram for OP to edit:

          _   _   _       _   _             _   _   _   _   _   _
Trig    _| |_| |_| |_____| |_| |___________| |_| |_| |_| |_| |_| |_
          _________       __________        _________   __________
Out     _| 3 s     |_____|   3 s    |______|   3 s   |_|   3 s    |__
  • \$\begingroup\$ tinyurl.com/yan47gc3 Also look at menu> Circuits> 555 timer circuits \$\endgroup\$ Sep 6, 2018 at 23:13
  • 1
    \$\begingroup\$ Welcome to EE.SE. We use timing diagrams rather than words to show how the circuit should respond to the trigger signal. I've given you a sample ASCII diagram in your question. Please edit this to show all the possible input conditions and output conditions for each. Use multiple diagrams if required. Note four spaces at the start of each line to be formatted in fixed-width font. What happens if the trigger remains on? \$\endgroup\$
    – Transistor
    Sep 6, 2018 at 23:16
  • \$\begingroup\$ That sounds cool Transistor, I hope I can use the timing diagram to demonstrate the circuit. I will try! Thanks \$\endgroup\$
    – user186623
    Sep 6, 2018 at 23:19
  • \$\begingroup\$ hmmm it looks like you already made it Transistor, just noticed that! Thats exactly what my whole paragraph is talking about, thats amazing man! Thanks! \$\endgroup\$
    – user186623
    Sep 6, 2018 at 23:22

1 Answer 1


It sounds like you are looking for a non-retriggerable timer (monostable multivibrator).

If so, that's exactly how the basic 555 monostable configuration behaves, with the caveat that the trigger input is active-low.

  • \$\begingroup\$ I just was watching videos about the Monostable multivibrator circuits and were almost what I'm looking for, I will keep checking and get back to you guys! Thats cool Dave! I appreciate your help! \$\endgroup\$
    – user186623
    Sep 6, 2018 at 23:34
  • \$\begingroup\$ tinyurl.com/y8fyubgq The only problem with your design, Raj, is lack of a unique sync pattern. \$\endgroup\$ Sep 7, 2018 at 0:10
  • \$\begingroup\$ Hello Tony, I'm afraid that I'm not sure about what you mean "unique sync pattern", would you please give more details? \$\endgroup\$
    – user186623
    Sep 7, 2018 at 1:24

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