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Help Required For Tachometer Circuit...

Posted: Wed Mar 08, 2017 11:19 am
by Lucille
I am trying to build a tachometer using IR Sensors..
I get good response at lower frequencies but as the frequency increases say to 170Hz it looses the wave..
i am using a hysteresis resistor of 1M at positive feedback and input is at inverting terminal of op-amp should i use hysteresis resistor i think the problem is with this as the frequency increases..
and if i remove the resistor response is so fast and ir sensor is imune to even little jerks..
Plz Someone give expert opinion.
Thanks In Advance