Electric Shock

电击

The primary variable for determining the severity of electric shock is the electric current which passes through the body. This current is of course dependent upon the voltage and the resistance of the path it follows through the body. An approximate general framework for shock effects is as follows:

决定电击严重程度的主要变量是通过人体的电流。这种电流当然取决于它通过人体所经过路径的电压和电阻。一个近似的总体框架如下：

Electric Current (1 second contact) 电流（1秒接触）	Physiological Effect 生理效应
1 mA 1 毫安	Threshold of feeling, tingling sensation. 感觉阈值，刺痛感。
10-20 mA 10-20 毫安	"Can't let go!" current - onset of sustained muscular contraction. '别放手！' 电流 - 持续肌肉收缩的开始。
100-300 mA	Ventricular fibrillation, fatal if continued. 室颤，若持续则致命。

One instructive example of the nature of voltage is the fact that a bird can sit on a high-voltage wire without harm, since both of its feet are at the same voltage. You can also see that the bird is not "grounded" -- you will not be shocked by touching a high voltage if there is no path for the current to reach the Earth or a different voltage point. Typically if you touch a 120 volt circuit with one hand, you can escape serious shock if you have insulating shoes which prevent a low-resistance path to ground. This fact has led to the common "hand-in-the-pocket" practice for engineers and electrical workers. If you keep one hand in your pocket when touching a circuit which might provide a shock, you are less likely to have the kind of path to ground which will result in a serious shock.

电压的本质的一个有启发性的例子是，鸟可以坐在高压线上而不会受到伤害，因为它的双脚处于相同的电压。你也可以看出，鸟并没有“接地”——如果你没有电流流到地球或另一个不同电压点的路径，触摸高压电不会被电击。通常，如果你用一只手触摸120伏电路，并且有绝缘鞋防止电流流到地面，你可以避免严重电击。这一事实导致了工程师和电气工人常见的“手插口袋”的做法。如果你在触摸可能触电的电路时把手插在口袋里，你就更不可能形成导致严重电击的路径。

More detailed table

更详细的表格

Conditions for dangerous shock

危险冲击的条件

Index

Voltage concepts

Practical circuit concepts

Reference
Nave & Nave
Ch 14

索引电压概念实用电路概念参考 Nave & Nave 第14章

HyperPhysics*****Electricity and magnetism

HyperPhysics ***** 电磁学

R Nave

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Current Involved in Electric Shock

电击涉及的电流

The electric current in amperes is the most important physiological varible which determines the severity of an electric shock. However, this current is in turn determined by the driving voltage and the resistance of the path which the current follows through the body. One difficulty in establishing the conditions for electrical safety is that a voltage which produces only a mild tingling sensation under one circumstance can be a lethal shock hazard under other conditions.

电流（单位为安培）是最重要的生理变量，它决定了电击的严重程度。然而，这种电流又由驱动电压和电流通过身体的路径的电阻决定。建立电气安全条件的一个困难在于，一种在某种情况下仅引起轻微刺感的电压，在其他情况下可能成为致命的电击危险。

Will the 120 volt common household voltage produce a dangerous shock? It depends!

If your body resistance is 100,000 ohms, then the current which would flow would be:

如果你的身体电阻是100,000欧姆，那么流过的电流将是：

But if you have just played a couple of sets of tennis, are sweaty and barefoot, then your resistance to ground might be as low as 1000 ohms. Then the current would be:

但如果你刚刚打了几局网球，又出汗又赤脚，那么你对地面的电阻可能低至1000欧。此时电流将是：