Found in a Philips publication from the 1970s, this circuit uses a DO040, which is difficult to obtain today. The circuit is powered by 12 V on pins indicated in the diagram.
This circuit produces a IR beam with a frequency adjusted by the 100k pot. The circuit can be used in...
This voice scrambler and descrambler circuit was found in a Radio Electronics from July 1963....
This transistor source was found in a 1990 documentation. 2N3055 transistors must be equipped with...