This circuit is from the time when photos were revealed in darkrooms. We found it in a 1968 Electronics World. The circuit can be used for other purposes.
This circuit was found in an American audio documentation from 1968. The configuration can be...
This circuit was found in 1980s American documentation. The transducer is a piezoelectric capsule and the...
This circuit is from an English magazine from 1976. By replacing the transistor for a BC548, the...