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One shot upon power-up...

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Rescue1

Member
I would like to build a circuit that will give a single pulse after power-up.Problem is I would like it to be approx. 10 seconds after power-up.When the circuit is powered down,it will reset and the whole process will start over again upon power up.Thank you for the help....

mozikluv

New Member
timer

hi,

what you need is an astable circuit. check out my post last Jan. 14, 2004, you will the formula to use.

Rescue1

Member
Thank you for the reply,and the great formulas... ...I am familiar with the 555,but what I want to do with this circuit might not have been written clearly by me.Upon power up,I would like a single pulse about 10 seconds after.Then the circuit would power down,or at least stop pulsing.Now a 555 can be set up for a single pulse,but how do I do it approx. 10 seconds after power up,as it would pulse again at some point.My thoughts were to use a cd 4017 counter on the 555 pulse,then set up the time interval so I could use one of the outputs of the 4017 approx. 10 seconds after power-up.The next output I can tie into a flip-flop,or latching relay to shut down the circuit,or pulsing.I think this setup will work,but I like to keep things simple,and feel this can be done by simpler means.Thank you for the help... :lol:

panic mode

Well-Known Member
did you think of two 555s?

ljcox

Well-Known Member
Power on reset

A Hex Schmitt Trigger such as the 40106 would be much simpler.
Design 2 RC timers in tandem. The first would time the 10 sec, the second 1 sec. Then use an AND gate to provide the 1 sec pulse.

Len

Rescue1

Member
Both are some great ideas.How could you get the second 555 to just give one pulse though...

Nigel Goodwin

Super Moderator
Rescue1 said:
Both are some great ideas.How could you get the second 555 to just give one pulse though...

Wire it as a single shot monostable.

Sebi

Active Member
Maybe this is a simple solution...

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