I need a circuit that when activate from a button it is on for about 30 sec.
I've tried whit a 555 timer but the problem is that it constantly draws a current of 4mA even if it isn't in use.
put a MOSFET in series with your load
put your momentary from the power to gate
add a cap from gate to ground
the momentary will charge the cap & gate turning the MOSFET on
the size of the cap will determine how long the gate stays on,
then the charge leaks away and the circuit turns off