The S-meter is a signal strength meter used in communication receivers. This circuit was found in a 303 Circuits from the 90s, European publication.
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...