This assembly is from 1957 from a Raytheon manual, but can be modernized using a BC548, 6 V power supply and common 100 mA relays.
The circuit shown is from the 1994 National Semiconductor Linear Applications Handbook. The...
This precision circuit, which also functions as a bridge, was found in a February 1967 Popular...
This circuit was obtained from a Hands On-Electronics, an American magazine from January 1987. This...