| 摘要 |
938,008. Transistor oscillator circuits. ERICSSON TELEPHONES Ltd. Jan. 19, 1961 [Oct. 21, 1959], No. 35617/59. Class 40 (6). A telephone ringing current generator comprises a push-pull transistor oscillator having a saturable core feed-back transformer formed from a single continuous tapped winding. The ringing generator shown comprises a pair of transistors with a saturable core auto-transformer coupling the emitter and the base circuits. Capacitors 129 and 130 are connected between collector and base electrodes to prevent voltage spikes being developed and an output terminal 145 is connected through a capacitor 136 which tunes the load circuit, the connection being to the end of the auto-transformer winding or to one of the tappings thereon. Specification 938,007 is referred to. |
