| 摘要 |
949,628. Converting. STANDARD TELEPHONES & CABLES Ltd. Feb. 17, 1961 [Feb. 24, 1960], No. 5948/61. Heading H2F. [Also in Division G3] A D.C. to D.C. converter comprising a transistor oscillator whose output is rectified by a diode 4, includes a circuit arrangement of transistors 6 and 9 and a Zener diode 8 to provide a stabilized output. An oscillator transistor 1 has its emitter-collector path in series with the primary winding of a transformer 2 across input terminals 21, 22. The transformer has a secondary winding connected to the diode 4 and a further winding 3 whose lower portion is a feedback winding connected to the base of transistor 1 and so wound that increasing collector current induces a voltage (negative upwards) to increase the base current through the transistor 6 and diode 10. A capacitor between the lower end of the winding 3 and the terminal 22 is positively changed with respect to 22. The increasing base current causes the collector current to rise until the transistor saturates when the voltages across the output winding and the winding 3 reverse, stored energy is discharged into the load and the transistor cuts-off. The voltage then appearing across the winding 3 is applied through diode 7 to charge a capacitor 12. This voltage is applied to the base of a transistor 9 whose collector-emitter path together with the emitter-base path of a transistor form effectively a variable resistance in the emitter base path of the transistor 1. This variation of the voltage on the base of transistor 9, which is a measure of the output voltage, acts on transistor 1 to keep the output constant. The supply for the transistors 6 and 9 is derived from the capacitor 14. A diode 11 is included to overcome difficulties attendant on a rise in temperature. |
