Using an 5V out voltage regulator LM7805/NTE960 with a project that doesn't always need to use the regulator and may run on a battery.
The regulator will always draw some milliamps from the battery even when everything is powered off (I have an MCU on another regulator than can power off components connected to this regulator when not needed).
This will reduce the time the battery can be used. How many milliamps will be used though? (If it's less than 5ma, then it's probably not worth worrying about).
I'd like to have a transistor connecting the GND pin on the regulator to actual ground. Then I think I can turn off the regulator by using the transistor.
I'm using a BC516 transistor, with the emitter connected to actual ground, collector connected to the GND pin on the regulator. When I measure the voltage between the Vout on the regulator to actual ground, I get 10V. When I measure the voltage between Vout and the GND pin, I get 3.4V, when in both cases I need 5V.