I have a circuit which requires exactly 12v to work properly, with a maximum tolerance of ±0.5V. The circuit is arbitrary and one can think of it as a theoretical question, but let's say that it usually takes between 0.1A and 1A (such as some Arduino + Servo Motor projects, for example).
In this sense, is it possible to make a circuit that only activates when the voltage is very close to 12v?
To be more specific, this circuit has some conditions:
- It should not produce significant current below 11v (or, if possible, no current at all). The circuit should be activated only close to 12v;
- It should not burn the entire device when the tension is above 13v. Above this voltage, the device must just turn off or somehow be prevented from being enabled until it goes back to 12v again. To be reasonable, it's not supposed to prevent voltages as high as 127v, but at least around up to 20v or so;
- Only one power supply must be provided, so the voltage limit/control/pass schematics must depend on that supply only. No cheating with external wall adapters or attached 9v batteries :)
In summary, it would be a simple circuit that prevents both under-voltage and over-voltage from the power supply by inhibiting the current to pass through the remaining circuit, keeping it active only when near 12v.
The chart below shows an example of how the circuit would be active (e.g., emitting some leds, driving some motors, etc) at that specific voltage range.
(Sorry if I put any strange terms, I'm from the biological sciences and just happened to grow an incessant curiosity for electronics)
Examples with integrated circuits are always welcome. But if possible, nothing too fancy, please. Unfortunately, there's no Texas Instruments in my country and the access to uncommon electronic parts is somewhat limited. That said, any reference would be acceptable as long as it helps to make this circuit possible.