Found in an 80's Elektor, this circuit can control loads up to 750 mA with the BD139 and 100 mA with the used transistor.
In the figure we have the way to activate a red LED that needs 1.7 V or even others with higher...
This circuit was obtained in a 1979 publication, but it can be assembled with the BD135 instead of the...
Found in Radio Electronics from the 90's, this circuit employs a 3140 operational amplifier, still...