| 摘要 |
<p>The circuit arrangement consists of two miniature relays (RE1, RE2), bridged for speak current by the condensers (C1, C2), always joined with one carrier (a, b) from the switching centre across the break contact units of the relay (2k2, 2k1), whereas the second carrier is connected to earth. On activation of one of the subscribers the earth current is closed across a contact relay (1k1, 1k2) connected to earth, which takes over a corresponding transistor (T1, T3) for spanning the reaction time of the switching centre, and whose disengagement and associated breaking of the earth connection of the switching centre is secured by an optocoupler (D1, D2, T2, T4) acting as a back-coupling. By this circuit arrangement independence from the reaction time of the switching centre is achieved.<IMAGE></p> |
