This 300 Hz to 3.4 kHz filter was found in the May 1989 Radio Electronics magazine. The circuit requires a symmetrical power supply.
This configuration, which uses a transistorized circuit in the feedback, provides a logarithmic response...
This receiver uses one of the first transistor types available on the market, the CK722, but it...
Suggested by General Electric in 1967 this circuit generates a single pulse when receiving a light signal...