Published in a February 1978 Radio Electronics magazine article, this digital circuit uses some of the integrated circuits of the time. The circuit uses a LED bargraph.
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...