Patent ID: 8625247
Filing Date: 2014-01-07
Classification: H01L,H01T,H02H

Abstract:
1. A protective circuit for input-side protection of an electronic appliance which operates in the microwave range against high-power interference pulses in the operating frequency range of the appliance, which protective circuit comprises, between an input and an output, a first limiter circuit with at least one gas discharge tube for limiting high interference power levels and a second limiter circuit, arranged behind the first limiter circuit, with semiconductor components for limiting lower interference power levels, wherein the first limiter circuit comprises two gas discharge tubes, connected in parallel, the two gas discharge tubes have a common gas space, the two gas discharge tubes are physically combined in one gas capsule, which comprises a cylindrical gas space with two mutually opposite end-face electrodes and a center electrode which is arranged in the center between the two end-face electrodes, wherein the end-face electrodes each form a respective electrode of one of the two gas discharge tubes, and the center electrode forms the other electrode of both of the two gas discharge tubes, and an electrically conductive flat plate is provided for electromagnetically decoupling the two gas discharge tubes from each other, the cylindrical gas capsule being inserted into said plate with its longitudinal axis at right angles to said plate and the two end-face electrodes on opposite sides of said plate, the plate thereby forming an electromagnetic shield between the end-face electrodes of the gas capsule.