This SCR circuit is intended to control an AC load with a low current switch. This switch can be a reed sensor. The load depends on the SCR.
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...