This circuit is from the 1968 ARLL documentation. The MOSFET admits equivalent and the coil determines the operating frequency range being the plug type.
This metering bridge circuit uses one power supply only. The operational ones depend on the...
This circuit was found in a 1992 documentation and has excellent sensitivity, using components that...
Found in ancient American documentation, this circuit produces a pulse every 8 Hz of a 400 Hz...