The UVTRON tube is an ultraviolet radiation sensor. In this circuit from Radio Electronics from April 1990 we have a flame detector.
This circuit activates an incandescent lamp at dusk and goes out at dawn. The sensor is an LDR and...
We found this circuit in a Philips documentation from 1969. It makes use of transistors of the...
This high input impedance tone control circuit was found in American documentation from the 1980s....