Have always wondered this.
Why can I touch a 7VDC 140A system with no problems, but 120V with less than a mA can kill?
In: Physics
As a very crude analogy:
Think of a wide river flowing slowly. This represents a low voltage (low pressure differential) and high current (a lot of water flowing per second). You can pretty easily swim in it.
Now consider a water cutting jet. This is a super high pressure jet (high voltage) but the total rate of water flow is small (low current). But if you put your hand in it, it will cut your hand off.
Or another analogy: Take a 5 lb hammer and rest it on your hand. Now take a pin and poke it into your hand with 5 lb of weight (same as the hammer). The first has the weight spread out (low pressure; ie low voltage) over your hand and there is no injury. The other has very high pressure at the point of the pin (ie high voltage) and will puncture your skin.
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