This input circuit for meters, which can also be used as a shield, is intended for operation with very low frequency signals. The power supply must be symmetrical.
Synchronized key. This circuit was found in a 1966 General Electric documentation. Modern...
This small receiver uses CK722 transistors and was found in a documentation by Hugo Gernsback from...
This circuit was found in a Popular Electronics from April 1993. It is a voltage regulator circuit...