This circuit was found in a Dutch documentation from 1970. The circuit makes use of semiconductors that have current equivalents and is indicated by a 0-5 mA milliammeter.
This circuit was obtained in an American documentation translated in the 80's. The circuit can be...
This circuit is from a 1998 Electronics Now and can be easily assembled since it uses a common...
This circuit was suggested by National Semiconductor in its Linear Application Handbook. The...