Found in a 1960s RCA documentation, this circuit applies to most common triacs. The trigger device is a neon lamp and the sensor is an LDR. R is typically 100k and C is 220 nF.
This is the traditional unijunction transistor relaxation oscillator circuit for the audio band. The...
This is half of a 4-channel amplifier from a system published in the October 1971 issue of Radio...
This circuit works both as a grid-dip (transistorized) and as an oscillator. The circuit is from a...