APPARAT OG FREMGANGSMAADE TIL AT BESKYTTE EN ELEKTRISK OMSKIFTERS KONTAKTER IMOD STROEMBOELGER

摘要

The contacts of an electrical switch (27), such as a magnetic contact reed switch or a magnetic contact reed relay used in a burglar alarm system, are protected from being fused together by transient current surges. This protection is accomplished by providing a normally nonconductive shunting path (28, 29) in parallel with the switch (27). The shunting path includes a voltage responsive device (29) which is biased to conduction in response to a current surge to thereby complete the shunting path and allow the current surge to bypass the switch (27).