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.
EDN magazine in a 90's issue published this TTL technology debouncer flip flop circuit, in this...
This circuit produces a 2 kHz tone on a standard piezoelectric transducer. The circuit can be used as...
This circuit can control the speed of Motors up to 2 A and voltages in the range between 3 and 12...