I have a solar powered circuit charging some super capacitors. Once the supercapcitors reach a certain voltage, say 7V, I want it to power the arduino and rest of the system. Then when the voltage drops below 5V (the arduino wont function properly), it cut's power to the circuit until it reaches 7V again.
Can you point me in the right direction of what I should be researching. I imagine I'll need to trigger a transistor (or relay) with a diode that blocks current until it hits 7V. But I need the transistor to remain open until it drops below 5V.