Menticol
Active Member
Hello guys!
I'm working on a very basic circuit to prevent battery over-discharge. It's a 741 op amp working as a comparator, and the results are... well, very predictable.
The Battery is a 12V, 7 Ah SLA, powering a home made emergency light. I think 10 volts is low enough to turn off the light.
The problem is, how can I power the circuit with the same battery wich the circuit is designed to protect?
Other schematics show a 5.1V zener diode to adress this problem, but the weather is too bad to go out to buy them.
I have 7805, 7809 voltage regulators in stock, but I guess they are unuseful for the purpose: Vcc must be higher than the voltage the circuit is intended to detect, right?
Thank you very much in advance
I'm working on a very basic circuit to prevent battery over-discharge. It's a 741 op amp working as a comparator, and the results are... well, very predictable.
The Battery is a 12V, 7 Ah SLA, powering a home made emergency light. I think 10 volts is low enough to turn off the light.
The problem is, how can I power the circuit with the same battery wich the circuit is designed to protect?
Other schematics show a 5.1V zener diode to adress this problem, but the weather is too bad to go out to buy them.
I have 7805, 7809 voltage regulators in stock, but I guess they are unuseful for the purpose: Vcc must be higher than the voltage the circuit is intended to detect, right?
Thank you very much in advance
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