| 摘要 |
<p>The application is to the supply of power to local circuits in telephone exchanges. The system uses identical voltage sources (U1, U2) feeding a common load (V). Each line to the load contains a semiconductor element (D1, D2), typically a diode or transistor, thus permitting only the highest voltage source to provide power. As the sources are nominally identical power will be drawn alternately in a semi random manner from both, but should one fail the blocking action of the series semiconductor will prevent an overload on the remaining healthy source due to the low impedance of thr failed one. Lower forward resistances can be achieved by employing transistors in parallel as the reverse blocking elements. The whole circuit may be of thin or thick film integrated circuit type.</p> |
