| 摘要 |
<p>Control circuitry uses first and second voltage sources 18 and 19 and first and second circuits across such sources. One circuit has a first energizable element 10 in series with a first diode arrangement 12 and 13 and the other circuit has a second energizable element 11 in series with a second diode arrangement 14. If the voltage difference V1-V2 of the sources is greater than a first value the first diode arrangement 12 and 13 is conductive and the energizable element 10 is energized, while if such voltage difference is less than a second value the second diode arrangement 14 is conductive and the second energizable element 11 is energized.</p> |
