This biestable vox circuit was found in an old documentation. The circuit makes use of components of the time (80's) and can work as a shield since the power is 5 V.
Details of the coil of this two-transistor generative receiver were not given. We found it in a...
This very high input impedance circuit is suggested by Texas Instruments. The circuit can be...
This circuit from an 80's publication also features low input capacitance. FET can be a modern...