It actually consists of a tunable field strength meter. The circuit is of an old documentation and the circuit must be tuned to the frequency to be monitored. The circuit offers the option to use a headset.
Three LM158, LM258, LM358, or LM2904 operational amplifiers are used in this instrumentation amplifier....
Found in a 90s 303 Circuits, this circuit aims to provide a soft start for a low voltage halogen lamp....
June 2017 - A wide variety of Rohm Semiconductor audio and codecs for audio is available from...