Operate a DC 9v relay with a small power


Can a lightbulb be switched on using two mobile phones? (Make a call and the bulb switches on)

I need this for a kid's school project so the questions like should the bulb keep glowing after the call ends do not bother. Its for a kid's school project so should be as simple as it could be.

Best Answer

I think something like the circuit below is good enough to switch your relay. I only drew the coil of the relay here.

Cropped Schematic