在中学物理教材中,把不高于36V的电压称为安全电压,有的同学就认为:只要是36V及以下的电压就一定是安全的。其实未必,对人体是否触电主要看流过人体的电流大小,研究表明,流过人体的电流的大小对肌体的危害程度是不同的。(1)当人体流过交流1mA或直流5mA电流时,人体就会有麻、刺、痛的感觉。(2)当人体流过交流20～50mA或直流80mA电流时,人就会产生麻痹、痉挛、刺痛、血压升高、呼吸困难,自己不能摆脱电源,就有生命危险。(3)当人体流过100mA以上电流时,人就会呼吸困难,心脏停跳。一般来说,10mA以下交流电流和50mA以下直流电流流过人体时,人能摆脱电源,故危险性不太大。 In the middle school physics textbook, the voltage not higher than 36V is called the safe voltage, and some students think that: as long as the voltage is 36V and below it must be safe. Actually not necessarily, whether the human body touches the electric current mainly depends on the size of the electric current flowing through the human body. Studies have shown that the magnitude of the electric current flowing through the human body is different to the damage degree of the body. (1) When the human body flows through 1mA of AC or 5mA of DC, the human body will feel hemp, thorn, and pain. (2) When the human body flows through an alternating current of 20 to 50 mA or a current of 80 mA, people will have paralysis, cramps, tingling, high blood pressure, and difficulty in breathing. (3) When the human body passes a current of more than 100 mA, people will have trouble breathing and the heart will stop. In general, when an AC current of 10 mA or less and a DC current of 50 mA or less flow through the human body, people can get rid of the power supply, so the risk is not too great.