You're given an electronic switch which requires 5V at 1mA in order to close; it is open with no voltage present at its input. If the only microphone available produces a peak voltage of 250mV, design a circuit which will energize the switch when someone speaks into the microphone.
The Attempt at a Solution
I really don't know how to start. Would I use an instrumentation amplifier or something else? If so, how would it be wired? Where would the signal from the microphone go?