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.
This circuit is from an 80's documentation, making use of PUTs that are not currently common...
This Linear Technology circuit was found in a 1980s documentation. The circuit can swing up to a...
This circuit is from an1966 General Electric documentation. The Triac can be equivalent to 6 A or...