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.
The circuit we present was found in an English magazine from 1980, but it can be easily assembled, as...
We found this circuit in an American documentation from the 90s. The circuit produces a 1 kHz...
By activating S1 the relay closes its contacts only after a certain time interval that depends on C1....