simplest least component momentary circuit

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pager48

Joined Nov 25, 2018
161
what would be the simplest circuit with least ammount of parts that makes a voltage of some constant amplitude (DC) for a defined duration (maybe 20-200mS) then turn off after it was triggered by some predefined millivolt DC voltage?
 

pmd34

Joined Feb 22, 2014
503
For the pulse you would be best using something like a NE555 or simpler still the MIC1555 (though its surface mounting). To trigger from a mili volt source you need a comparator chip. To be really simple you can look for a comparator that has a small "Input referred positive trip point" (or so its called in on data sheet). This means you can then connect the (-) input to 0V and as soon as your signal voltage fed into the (+) side goes above this trip voltage it will trigger the comparator & pulse.

If you want to prevent the possibility of re-triggering the pulse during the pulse time, you should use something like the 74HC221 logic gate.
 

danadak

Joined Mar 10, 2018
4,057
Is this a one off design or a high volume design ?

What is the magnitude of the voltage you want to generate and how much
power does it have to deliver ? The accuracy of the desired voltage ?

Trigger V accuracy ?

Any spec on latency from trigger to output voltage ?


Regards, Dana.
 

eetech00

Joined Jun 8, 2013
1,869
what would be the simplest circuit with least ammount of parts that makes a voltage of some constant amplitude (DC) for a defined duration (maybe 20-200mS) then turn off after it was triggered by some predefined millivolt DC voltage?
Hi

Too general a question.

We need more specificity for the trigger input requirements, output requirements as supply requirements..

eT
 

crutschow

Joined Mar 14, 2008
24,730
Yes, many questions.
What is the input voltage trigger range?
What is the input voltage trigger duration (min and max)?
Will the input pulse duration be longer than the desired output pulse duration?

An LM339 comparator can likely be used to generate the pulse, but more info is needed.
 
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