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Question about comparator and 555 timer circuit

Posted: Fri Jul 28, 2017 10:39 am
by miyayoung
I'm designing my first circuit for a university project.

This circuit will check the voltage of two sensors. If both are over a reference voltage and persist as such for more than one second, a relay will switch on. Until I switch off the entire circuit by pushing the master switch, the relay must be closed.

I'll using op-amp LM393 for the two comparators, NE555N with the RC circuit (charging of capacitor lasts one second), the AND gate to verify both the conditions of the comparators, and the OR gate to maintain the power to the NE555 until I switch the master switch.

In your opinion will it work?

The power supply of the op-amp and the gates is taken from +VBAT.