| 摘要 |
1461235 Automatic current control COMPAGNIE INDUSTRIELLE DES TELECOMMUNICATIONS CIT-ALCATEL 23 Jan 1975 [24 Jan 1974] 2933/75 Heading G3R A series transistor current regulator includes a current sensing resistor and a constant voltage diode supplied with stabilized current from a resistor network. The diode is connected to the base of the series transistor through the basecollector path of a second transistor and a second constant voltage diode. The base-emitter junction of a third transistor is connected across the series connection of the current sensing resistor and the first diode. As shown, a two-terminal network 2 is connected between a D.C. source 1 and a resistive load 3 in a repeatered telecommunications line. The current is sensed by a resistor 5, the potential across which controls the conductivity of a transistor 12, which in turn controls series transistor 4. A reference potential is provided by a Zener diode 10 which receives a constant current supply from a transistor 9, resistors 7, 11, 13, 14 and a second Zener diode 8. A parallel resistor 6 limits the power dissipated in the series transistor 4, and a pair of Zener diodes 17, 18 limit the total voltage across the network 2. Diodes 15, 16 provide temperature compensation. If a high supply voltage and/or low resistance load are used, several networks of the illustrated.type may be connected in series. |
