Exchange battery supplied circuitry for DC=DC converter - uses RC generator in conjunction with switching circuits to provide DC symmetrical voltage for telephone subscriber's appts.

摘要

The sec. winding (3, 5) of a transformer is centre-tanned (4) to produce two symmetrical opposite voltages (+5V/-5V) with rectifying diodes (D2/D3). The output voltages (+5V/-5V) are connected to a regulator circuit (SRG), which includes a switch (S2), and is connected to switching circuits (S1, S3) to rectify any errors in the voltage symmetry of the outputs (+5V/-5V). ADVANTAGE - Simple circuit with voltage and current regulation. Short circuit in any internal circuit does not lead to damage by heat generation.