Hello all,
Would someone mind giving me advice on a circuit to switch on/off a 12v automotive relay based on a 1v-4v threshold from a 0v-5v signal.
The relay was switched to ground by ECU at one point and has a resistor in the relay itself. (note: I'm reusing an extra relay, NOT altering the function of an existing relay) I measure 60.4 Ohm across the coil leads.
I want to switch on the relay (either to ground or 12v+ whichever is better for the final circuit, BUT switching to GND is preferred) when the MAP sensor reads ~5psi above atm. But I don't want to switch the relay off until MAP reads below ~1-2psi (hysteresis). I'd also like both thresholds to be adjustable.
I'd like the circuit to use either a lm393 or lm358 which I have on hand.
And if possible not require a regulated 5v+ or 12V+. The car and relay will be running ~13.2-14v off the alternator.
The thresholds can be allowed to fluctuate with alternator voltage to simplify the circuit.
Relay will drive a secondary fuel pump.
Thanks in advance!
Rey
Would someone mind giving me advice on a circuit to switch on/off a 12v automotive relay based on a 1v-4v threshold from a 0v-5v signal.
The relay was switched to ground by ECU at one point and has a resistor in the relay itself. (note: I'm reusing an extra relay, NOT altering the function of an existing relay) I measure 60.4 Ohm across the coil leads.
I want to switch on the relay (either to ground or 12v+ whichever is better for the final circuit, BUT switching to GND is preferred) when the MAP sensor reads ~5psi above atm. But I don't want to switch the relay off until MAP reads below ~1-2psi (hysteresis). I'd also like both thresholds to be adjustable.
I'd like the circuit to use either a lm393 or lm358 which I have on hand.
And if possible not require a regulated 5v+ or 12V+. The car and relay will be running ~13.2-14v off the alternator.
The thresholds can be allowed to fluctuate with alternator voltage to simplify the circuit.
Relay will drive a secondary fuel pump.
Thanks in advance!
Rey
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