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One shot or 10Hz trigger source

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New Member
I would like to build a pulse generator that can be used as a single shot or in 10Hz mode by simply flipping a toggle switch to select one mode or the other. The ICs I currently have that would be suitable are:


*I may have a couple of other common TTL or CMOS devices floating around that can be used as well.

My thought for the 555 timer to achieve 10Hz:
Short pins 2 & 6
Series 33K + 39K ohms between pins 3 & 6
1uF cap from pin 2 to ground

Application of this circuit:
To drive a (large) photo flash circuit.


New Member
555 solution

from what i get from your problem, I think a simple monostable set up of a 555 timer may save the problem. The time delay is easily calculated with the formula: time constant = C1 * R1, a time constant is the amount of time a capacitor takes to charge something like 63.2% of the remaining charge. A 555 triggers at 2/3 of vcc (with a 9v power to chip itll trigger when capacitor is at 6 volts) adjust it like you need...

If youre not a techno-peasant or anything, sorry, im just a student in electronics so i try to explain it in simplest term, i hope that helps.



New Member
timer circuit

:D hi,

am not sure what you want base on your post, you said you need a one shot trigger but on the circuit connection you have cited it was configured to funtion as a self resetting circuit. if what you really need is a one shot, then do the monostable mode. :)
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