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.
The frequency of this astable depends on the capacitor that can be changed over a wide range of...
This circuit is from a documentation from the 90s. The transistor can be any general-purpose FET...
In the figure we have one of the many options found in this section for an intercom using ordinary...