| 摘要 |
<p>A frequency-dependent overvoltage protective device for high voltage appliances comprising in principle two varistors 10, 11 connected in series, whereby at least a capacitor 9 is connected in parallel to varistor 11, said varistors 10 and 11 ensuring protection at the normal network frequencies, while in the case of higher frequencies, as a consequence of capacitor 9, the voltage over the varistor 10 increases so that then this element alone taken over the protection.</p> |
