Is there a circuit or device that can be used to switch on a low power circuit without itself using power? I am trying to take the output (min. 30-50mV) from a photodiode and use it to turn on a circuit that is connected to a +5V power source (4-AAA batteries). However, the switch itself can not draw any power.
I have tried using an NPN BJT. But it took 735mV to turn on the circuit and I can only use about 30-50mV. Thank you for any help.
Dave
I have tried using an NPN BJT. But it took 735mV to turn on the circuit and I can only use about 30-50mV. Thank you for any help.
Dave