Siemens arrester, used with radio equipment. An arrester protects a radio from the effects of lightning strikes on an aerial. When the voltage across a gap between two conducting blocks exceeds a certain level, the air breaks down and conducts the lightning current to ground.

Physical Description

Two possibly graphite blocks separated by a small gap mounted on an insulting material (mounted in turn on wooden base), with a glass bodied fuse mounted next to the blocks.

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