近日KTV电死人新闻又出现,不久前还有IPHONE电死空姐的新闻 为何总有这类新闻发生?为何人们总没学到教训? 或是缺少了科学的讨论,无法准确地抓到问题所在呢? 首先,我们可以看到这个关于XLR插头的词条: http://en.wikipedia.org/wiki/XLR_connector Although covered inindustry technical standards, there is still some disagreement on the best wayto handle the use of pin 1 for grounding (earthing). The main controversy iswhether the shell of the connector should be connected to pin 1 or the shield,or left floating. 行业技术标准目前在一脚接地上仍然有很大的分岐意见。 主要的争议是连接器的外壳是否应连接到1脚，或是只接到1脚,而外壳是悬空不接! AES standards mentionedabove recommend that shells of cable-mounted connectors should never beconnected to pin 1 or the shield, because inadvertent contact of the shell withanother grounded surface while in use can create unwanted current paths forfault current, potentially causing hum and other noise. 在AES标准上,电缆安装连接器的外壳永远不会被连接到1脚与电线屏蔽层 或是另一接地表面的外壳!因为不慎接触到其他地面，会在使用中造成不必要的电流路径与故障电流，可能造成的嗡嗡声和其他噪音。 On the other hand,equipment containing active circuitry should always have pin 1 connected to theconductive enclosure of the equipment as close as possible to the point wherethe signal enters the enclosure. The argument centers around the radiofrequency shielding provided by the shell of the connector, which may bereduced if it is left floating. 另一方面的论点是在射频上做考虑,这一方认为:有源的电路的设备应该始终将壳体与相连接,其中信号进入外壳的导电外壳。这样会降低射频干扰,如果是悬空的,那这样的抗干扰程度可能会降低 这几句话浅浅带过,但也值得你我好好思考! 詳全文