Circuit provision for the symmetric power supply of call circuits in telecommunication plans. (Machine-translation by Google Translate, not legally binding)

摘要

A circuit arrangement for the symmetric supply of call circuits in telecommunication exchanges, which serves for an intermittent supply of terminal equipment with a direct current potential, on which an alternating current call potential is superimposed and in which potential is applied from a call-alternating-current potential supply, having an output transformer comprising two symmetrical halves and from a dc potential supply, the calling circuit comprising a series circuit including the first half of the output winding of the output transformer, the supply of dc potential and the second half of the output winding of the output transformer, the change of direct current potential to the dc potential over which the call potential is superimposed of alternating current, by means of semicondu devices switching factors, including the direct current circuit transistors, including the circuit for the direct current potential over which the alternating current potential is superimposed, bipolar thyristors (triacs) and said semiconductor switching devices are controlled for the non-switching interval. Call (direct current power supply only) and for the call signal (supply of a call ac potential on which the direct current potential is superimposed) by a control unit, according to the time control of the call (non-call interval sequence and call signal), characterized in that it also comprises a monitor unit (u11) which in response to the extinction of only one of the two bipolar tiristors (triacs) (tri11 and tri21), during the change of call signal to the non-called interval provides an additional trigger pulse to the electrode of shot (door) of said triac (tri11 or tri21). (Machine-translation by Google Translate, not legally binding)