This circuit was obtained in a 1980s publication, but it can be easily assembled today, as all components are common. The transformer is 12 + 12 V with at least 1 A and the diodes 1N4002.
This 1-transistor circuit appeared in a February 1962 Radio Electronics. The coils for the...
This recyclable automatic timer was found in Radio Electronics magazine from July 1960. The...
This transistor tester was found in a publication by Gernsback from 1960. The circuit can be used...