Found in an American publication of 1968, this circuit makes use of a pilot light of the time. It can be replaced with LED with appropriate series resistor. Transistors may be modern equivalents.
This circuit was found in a 2003 documentation. Its purpose is to check if the transmitter of an...
Found in old English documentation this circuit evaluates the power of a transmitter. The circuit has...
The circuit shown is suggested by National Semiconductor's Linear Applications Handbook. The base...