Varistor using zinc oxide moulding with specific shape - provides overload protection for high frequency transmission cables

摘要

The varistor has a rotationally symmetric sintered body (1) made of metal oxide with a bore contg. one electrode (2) and a periphery provided with an external electrode (3). Electrode (2) is pref. a wire, whereas electrode (3) is a metal-coating or -sheath. Body (1) pref. has a double-hyperboloid contour on wire (2) leading to a max. dia. with coating (3) or a concentric tubular sheath (3). Body (1) is esp. ZnO; and electrodes (2,3) have connections for electric cables. Used to provide effective overload protection for electric appts. and concentric cables at high frequencies, i.e. above ca. 1 MHz in transmission systems using carrier frequencies. The varistor can be inserted between the inner- and outer- cable in a concentric cable.