| 摘要 |
For determining the position of a switch and for monitoring the connecting line for short circuits and interruptions, threshold stages containing Zener diodes are provided. A voltage or a current having periodically changing amplitude, preferably a triangular waveform, is fed to the switch via the line being monitored. The threshold voltages of the Zener diodes may be equal or staggered, depending on the manner of connection of the diodes in the circuit. For instance, if a Zener diode is connected in series with the switch, which may be either make contact or break contact and a Zener diode is shunted across the switch, Zener diodes with the same threshold voltage are used. |
