This 600 kHz circuit is designed to locate a lost boat anchor. The circuit has a range of up to 10 meters. The transistor admits equivalent.
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...