How to make 3 secs delay in 555 timer?

Discussion in 'The Projects Forum' started by Erwin Mag-Iba, Feb 18, 2018.

  1. Erwin Mag-Iba

    Thread Starter New Member

    Feb 18, 2018
    I have a problem designing my project. How to make a 555timer delay for about 3secs?
    My problem is when I push the switch for a long time and the output has nothing as I released it. While if I just tap it the output got 3secs delay.

    I'm working on a boom barrier design without using microcontrollers and arduino.
    Any suggestions is much appreciated! Thank you in advance.
  2. nerdegutta


    Dec 15, 2009
    Hi, and welcome to AAC.

    Do you have a schema or a picture of a breadboard? It's easier to give proper guidance when we see what you are doing. Have you used Google and searched for 555 timer circuits?
  3. dl324

    AAC Fanatic!

    Mar 30, 2015
    Welcome to AAC!
    This doesn't make sense.
    Read the datasheet. The trigger input needs to be above 1/3 Vcc before the timer times out. Otherwise output will be HIGH as long as the trigger input is LOW.

    Put a pull-up resistor on the trigger input and AC couple the trigger signal.