This simple neon lamp oscillator produces a 140 Hz, 40 V peak-to-peak signal. The frequency is given by the capacitor that can have its value changed. Note the high supply voltage.
This 3-transistor circuit is from a Radio Electronics magazine from May 1963. The transistors used...
This is the traditional configuration for a limit comparator or window comparator, using two...
This circuit was found in a 1966 General Electric publication. The circuit applies to other triacs...