Electrical question - Voltage compare?
I have an application where I'd like to have an incoming voltage dictate whether a solenoid is fired or not. If the incoming voltage is lower than a specified amount, a switch will allow a battery to supply power to the solenoid. I need help to figure out how to accomplish this. Any assistance is much appreciated.
Update:Would you be able to suggest one for me to purchase in order to experiment with? I'm probably looking at low voltages (~0-5V).
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Umm, this is relatively simple. Use a comparator with a voltage reference to detect the voltage then use that to drive a relay, which switches the solenoid from the incoming to a battery.
Assuming this is DC.
edit:
"comparators I've seen fire when the incoming voltage is higher than the reference. Is there certain kind that fires if it is lower"
Actually, a comparator works both ways, by definition. Input higher than the reference, the output is in one state, lower than the reference, it is in the opposite state.
ALL comparators work wiht voltages above and below the reference, that is what a comparator does.
edit, just about any comparator will work. LM339 has 4 comparators in one package. But you need other components, voltage supply, voltage reference, resistors, etc, plus knowledge.
Use a comparator with an input for your reference voltage (trip point) and the other in put connects to ur incoming voltage. The output should connect to a driver circuit.
What sort of voltage input? AC, DC? How accurate must it be?
A fixed threshold comparator will do the job for a DC input voltage. For an AC input, you'll need to rectify it and monitor the DC level out of the rectifier.