This circuit was found in American documentation from the 90's. The transformer is of the high voltage type for old light advertisements.
This circuit with variable capacitance diode (varicap) is from a publication from the 90s. The...
With this circuit it is possible to divide the frequency of a rectangular signal by values between 2...
The presented circuit uses an optocoupler to trigger a triac. We found it in a Popular Electronics from...