Found in an English publication from the 1980s, this circuit can be built with equivalent transistors such as the BC549. The signal must be applied to an external amplifier.
This circuit was found in a 1990 Electronics Handbook. The transistors can also be the BC548 and...
This circuit can be used to obtain control signals from an infrared emitting source. The circuit is...
The integrated circuit used in this project is not the most common. The use of a crystal...