The purpose of this circuit is to check the linearity of SSB amplifiers. The circuit was found in an old documentation for hams. The diode is a general purpose detector type.
When the temperature rises above the value adjusted by P1 the relay triggers on. The rated voltage for the...
This circuit was found in a Popular Electronics of the 90s. We can build it based on modern...
We found this circuit in a 1965 publication by General Electric. The zener is 8.2 V x 1 W and the...