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We've all learnt about their differences, amps are for current and voltage are for potential difference. They are proportional with resistance and all that.

I'm confused by their purpose. What are the effects of a high current compared to a high voltage?

In those pylons, they have a high voltage to reduce current and resistance, and waste less energy, I think. But if they are all linked in v=a*r, how does that work? How do you get a high voltage and low current, and vice versa?

And another thing. Some devices are current-dependent, and others voltage. Why? What factor decides that? I think a laser diode is current-dependent, so how does voltage affect its performance?

Tasers on the other hand are more voltage based, having lots of that and just a few milliamps of current. Why does this device need more voltage? This leads to another question. Why do danger signs say "high voltage" when the current is the killer? If the voltage is really so dangerous, a taser can have up to 50000 V, so...?

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voltage requires electric fields; once the fields are in place, no further electron movement is required.

amperage is moving electrons.

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The hose pipe analogy.

The amount of water flowing per second is the current. The pressure is voltage, and resistance is the inverse of the diameter of the pipe. To increase total amount of water you either need to increase the pressure, or increase the diameter of the pipe.

As for danger... a tiny diameter pipe at high pressure is not going to do you a lot of damage. Nor is a large amount of water at low pressure. Of course, at the extremes the high pressure jet might puncture you and the large amount might drown you.

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  • \$\begingroup\$ thats actually a really nice explaination. So about the dangers, what you are saying is there must be a balance between current and voltage to be effective, but an extreme amount of voltage can still be harmful? \$\endgroup\$ Feb 22 '20 at 15:41
  • \$\begingroup\$ @CookieDookie Like they say, it's the current that kills. In general, "dangerous" is around 30 millamps and "possibly fatal" starts at about 100. Sometimes high voltage is needed to drive that amount through the body, and sometimes much less (like when you are wet and your resistance goes way down). However, high voltage at low current can still cause burns in some cases. For example 10kV at 10mA is 100Watts and a lot of that is going to be dissipated in the skin. \$\endgroup\$ Feb 22 '20 at 16:04

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