This circuit for analog telephones from the 90s was found in documentation from the time. It lights up a remote LED when the extension is in use.
The base of this circuit is 1/4 of an integrated circuit 4136 which consists of a quadruple 741....
This circuit has a common configuration widely used in projects on this site. The transistor is...
This circuit appears elsewhere in this section and on this site. The circuit generates a linear...