| 摘要 |
1,067,490. Keying carrier frequencies. ASSOCIATED ELECTRICAL INDUSTRIES Ltd. Feb. 7, 1966 [Dec. 21, 1964], No. 51841/64. Heading H3R. A transistor oscillator comprising a transformer with windings (W1 and W2) providing feedback from the collector circuit to the base circuit, is characterized in that a third winding (W4) of the transformer is shunted by a semiconductor diode (D1) which may be forwardly biased to prevent oscillation. The diode (D1) may be connected to keying terminals through a Zener diode (D3) so that oscillation can only be stopped when the applied voltage is sufficient to break down the Zener diode, and a further diode (D2) may be connected in series to prevent flow of oscillatory current in the external circuit. The transformer may be provided with an output winding (W3). |
