| 摘要 |
<p>The remote switching device uses a single control wire to switch on electrical equipment (10). The transmitter section (20) converts the mains voltage at the input (E1, E2) to a rectified and smoothed direct control voltage (S1). The control wire (16) signal is compared with the neutral mains line (C4) in a low pass filter (22) of each individual equipment. When the control signal is "low", the filter ensures that the neutral line voltage is strongly attenuated so that residual oscillation at the filter output are less than one millivolt, ensuring that the electrical equipment (10) is switched off. When the control signal is "high" the d.c. signal passes through the filter to switch on the equipment. The passive filter can be replaced by an active filter, and several devices can be used to control several parallel equipment units.</p> |
