Found in Datel's documentation from the 1980s, this circuit makes use of the company's operational amplifiers. The circuit can be implemented with any modern equivalent operational.
This simple earphone receiver was sold in the 1960s in Japan. The circuit uses a single germanium...
This headphone amplifier using a pickup coil can be used as an extension for devices such as TVs,...
The UM3562 integrated circuit (not very easy to find) synthesizes three types of sound that...