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An electric match is a device that uses an externally applied electric current to ignite a combustible compound. Electric matches use a bridgewire consisting of a heating element to ignite a pyrogen, which is a quantity of readily ignited pyrotechnic initiator composition. Electric matches can be used in any application where source of heat is needed at a precisely controlled point in time, typically to ignite a propellant or explosive. Examples include airbags, pyrotechnics, and military or commercial explosives. == Design == Electric matches consist of two parts, a bridgewire and a pyrogen. The bridgewire is a heating element, typically in the form of a loop or coil of thin wire, which is encased in the pyrogen, which is a quantity of readily ignited pyrotechnic initiator composition. If the pyrogen is sufficiently conductive, it can act as the bridgewire as well. Electric matches also come with provisions for attaching an electric current source, and they may be provided with a protective cover and/or a means to attach them to the device to be ignited.〔〔〔 To operate an electric match, a source of electricity of appropriate voltage and current is needed to provide current to the match. When sufficient electric current is passed through the bridgewire, the resistive heating causes the element to rise above the ignition temperature of the pyrogen, and the pyrogen begins to burn.〔〔 Commercial electric match manufacturers often specify 3 key parameters of an electric match: the resistance (often around 2 Ohm), a recommended firing current (often around 1 A), and a maximum no-fire current. The "test" button on a firing systems typically tests a setup by sending a current limited to well below the no-fire current (often 0.2 A) to detect common problems (short circuits and disconnected open circuits).〔〔〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「electric match」の詳細全文を読む スポンサード リンク
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