| 摘要 |
<p>A piezoelectric chip (1) has two electrodes (13,14) on one side and two corresp. electrodes (13',14') on the other side. The piezoelectric chip decouples the input control circuit (9) from the semiconductor switch (10), which may be a triac, a thyristor or a MOS power FET. One pair (13,13') of electrodes acts as input and is connected to the output of the control circuit and the other pair (14,14') acts as output and is connected to the semiconductor switch. The electrodes may take various forms, e.g. concentric rings, rectangular or semicircular. An additional pair of electrodes may be incorporated to provide a second output for controlling a second semiconductor switch. The frequency of the a.c. voltage produced by the control circuit and the resonant frequency of the piezoelectric chip are matched to one another for a given vibration mode of the chip.</p> |
