repeating pulse timer help needed

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

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?

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

ken

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

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)