Found in documentation from the 1980s, this circuit uses a SG1524. It is an uncommon integrated circuit nowadays. The circuit provides a current of 20 mA with a symmetrical voltage between 15 and 18 V.
This circuit activates a recorder from the signal obtained from a telephone line in the service. It is...
This circuit was found in the August 1972 issue of Radio Electronics magazine. The circuit...
This digital potentiometer is from a 1993 publication, but it can be easily assembled today. R1 to...