Help With One Shot

L

Larry Watkins

New Member

• Mar 25, 2017

• #1

I need a circuit with an approximate one second pulse output delayed by three or four seconds when triggered that uses twelve volts dc. I can find delayed on circuits that don't shut off. Is this possible with a 555 timer?

 

K

KMoffett

Well-Known Member

• Mar 25, 2017

• #2

You would need two 555s or a 556. the first one (section) as a monostable gives you the delay. The second (section) as a monostable, outputs the one second pulse.
**broken link removed** See Two Stage Time Delay Circuit

Ken

 

MikeMl

Well-Known Member

Most Helpful Member

• Mar 25, 2017

• #3

What does your trigger input look like? Level? Edge? Polarity?

 

Tony Stewart

Well-Known Member

Most Helpful Member

• Mar 26, 2017

• #4

Input = momentary switch to gnd or V+? or don't care
Output=highside switch for 1 sec after 3~4sec delay to 12V at what output current level or DC resistance ? and also non-retrigerable or don't care or what ? during these time periods

 

L

Larry Watkins

New Member

• Mar 30, 2017

• #5

Thanks for the replies! You've been very helpful. The one shot would trigger a relay set for ten or twenty seconds. The relay would output 120 ac at fairly low current. I'm still working on it but may have a solution.
Thanx