This telecommunications circuit was found in a National Semiconductor publication from the 90s. It is intended to convert the voltage from 48 V of telephone lines to 5 V with currents up to 1 A.
We found this circuit in a 1967 Electronics World. The circuit can be designed to control other...
The presented circuit monitors a line indicating if it is busy if there is an extension. The...
This circuit is from old documentation. The operational amplifier is uncommon nowadays. The...