repeating pulse timer help needed

[jimcreeper]

I am just learning this stuff. I know I need to use a 555 timer chip most likely.

I need a circuit that will repeat a pulse once started and continue to pulse until stopped. I need to be able to adjust the time between pulses from 1sec to 15 mins. The pulse will be needed to fire an electromagnet of a sort to do small mechanical work.

Jim

 

[MikeMl]

Does "starting/stopping" the circuit mean applying/removing power to it?

15min is too long for an analog timer because of capacitor leakage issues. How accurate do you want the timing period to be?

 

[KMoffett]

How long is the "pulse"? You might take a look at these timer circuits...particularly the Repeat Interval Timers: **broken link removed**

ken

 

[jimcreeper]

starting and stopping starts the pulsing.

The length between pulses could be as low as 1sec-5mins, more then 5mins would be nice.

The time length of the pulse would be about .5sec, just enoff to trick a switch.

Those circuits wont do like what I said, I have had a good look around, with no luck.

Jim

 

[MikeMl]

This circuit I posted in this thread comes real close to what you need.

Is your pulse high for the short duration? If so, you would have to reconfigure the output transistor.

(Done)