Overvoltage protection for electronic telephone station - has transistors in microprocessor-controlled circuit arranged to function as switch and limiter

The telephone stations are fed from the exchange battery over the subscriber pair with pole protection at the circuit input parallel to both lines. Behind the protection in one line G first ohmic resister and a source-drain path of a longitudinal transistor as NSI contact are connected in series. On...

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Bibliographische Detailangaben
Hauptverfasser:	KLEIN-REESINK, LUDGER, 4426 VREDEN, DE, IBSCHER, KARL, 4290 BOCHOLT, DE
Format:	Patent
Sprache:	eng ; ger
Schlagworte:	ELECTRIC COMMUNICATION TECHNIQUE ELECTRICITY TELEPHONIC COMMUNICATION
Online-Zugang:	Volltext bestellen
Tags:	Tag hinzufügen Keine Tags, Fügen Sie den ersten Tag hinzu!

Beschreibung
Zusammenfassung:	The telephone stations are fed from the exchange battery over the subscriber pair with pole protection at the circuit input parallel to both lines. Behind the protection in one line G first ohmic resister and a source-drain path of a longitudinal transistor as NSI contact are connected in series. One line (c) of a subscriber pair (T1) has, behind the pole protection (G1), a negative potential, while the other line (d) has a positive potential. The transistor circuit consists of a PNP-transistor (T2), whose base is energised by an ohmic resistor (R3) via its emitter-collector path. The transistor control voltage (UI) is connected via another ohmic resister (R4) to a NPN-transistor (T3). ADVANTAGE - Low-cost and simple realisation of overvoltage protection circuit.