I found tis circuit in na old documentation from 1958. The circuit uses germanium transistor availble that time and hard to obtain today. The circuit is indicated for phono applications using variable reluctance transducer.
Found in a 90s Popular Electronics, this circuit interfaces the telephone line with an audio...
This excellent rectangular signal generator was found in a 1989 Radio Electronics. The ranges are...
This circuit was found in the July 1992 issue of Radio Electronics magazine. The circuit is based...