We found this circuit in the November 1974 Radio Electronics magazine. The capacitors determine the output time, and it is normal to obtain 1 second for each uF used.
This circuit can be used to control loads up to 500 mA from the outputs of microcontrollers such...
This circuit with transistors in parallel was found in a Radio Electronics of August 1952....
This Linear Technology circuit can measure currents from 100 pA to 100 uA. The circuit is from the...