This circuit for alternating current loads has a built-in timer. SCR2 is according to the motor current and must be equipped with a heat sink. The circuit is from a 70s GE documentation.
This Rytron transmitter was published in a 1953 book. The circuit can be implemented with a BC558...
Foto-Darlington for applications such as light sensor. In normal applications only the collector and...
This circuit was found in a 90s Popular Electronics. It generates tones given by the oscillators and...