Found in a 1960 General Electric documentation, this crowbar circuit blows the fuse in case of excess current. The circuit is for 12 V sources triggering between 14 and 17 V.
This circuit is from a 1995 technical documentation. The transistor can be a BC558 and the sensor...
Found in a Popular Electronics from the 90s, this circuit checks the presence of voltage on a...
The critical component of this amplifier is the output transformer. We found the circuit in an old...