This circuit is from an American documentation from 1975. The circuit uses components of the time which can be replaced by modern equivalents. The coupler is homemade with a lamp and a photocell.
This circuit generates pulses at a frequency that can be adjusted by a potentiometer. The circuit is...
This oscillator uses a small IF transformer taken from an old transistor radio. FET admits...
Found in a 1970 EEE, this circuit generates signals that depend on the C1 capacitor. Transistors are...