How to make 3 secs delay in 555 timer?

Thread Starter

Erwin Mag-Iba

Joined Feb 18, 2018
1
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.
 

nerdegutta

Joined Dec 15, 2009
2,675
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?
 

dl324

Joined Mar 30, 2015
9,329
Welcome to AAC!
My problem is when I push the switch for a long time and the output has nothing as I released it.
This doesn't make sense.
While if I just tap it the output got 3secs delay.
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.
 
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