| 摘要 |
912,616. Automatic voltage-control systems. SIEMENS SCHUCKERTWERKE A.G. Dec. 19, 1958 [Dec. 20, 1957], No. 41124/58. Class 38 (4). In a D.C. voltage stabilizer of the shunt transistor type, the transistor is either directly controlled by a Zener diode, or forms part of a bi-stable circuit which is switched by an auxiliary transistor controlled by a Zener diode. In one embodiment, Fig. 1, a transistor 7 is connected in series with a resistor 8 across the output of a bridge rectifier 4 and a resistor 3 is included in the A.C. input to the rectifier. A Zener diode 9 is connected between base and the negative line so that any increase in output voltage is compensated by an increase in the current passed by transistor 7. In a second embodiment, Fig. 2, the shunt transistor 11 forms a bi-stable pair with a second transistor 13, and is rendered conducting or non-conducting according to whether or not the portion of the output voltage tapped off a potential divider 21, 22 exceeds the reference voltage of a Zener diode 20 which controls a third transistor 17. The diode 20 is maintained conductive by a higher voltage supply from the input terminal via a resistor 23. In a third embodiment, Fig. 3 (not shown), the Zener diode controlled transistor is of NPN type and is coupled to the shunt transistor by an amplifier; overall positive feedback providing the switching action. |
