Sunday, 12 January 2014

Resistance is useless

I measured my resistance today. The lowest I could get it, was across one hand, with wet fingers, and that was 50 kilo-ohms. Dry, or across both hands, more like 100.

Why is this important?

I'm thinking of a future bike I might build, using a 48 volt battery. The question is, can I electrocute myself with that, or even get a nasty shock?

The strength of shock depends on the current; 5 milliamps DC is considered to be so small you won't feel it. And if I'm 50 k-ohms, then the current from 50 volts would be 1 milliamp.

If this were AC at 240 volts (like the UK mains), then I'd conduct 5 milliamps, and that's a pretty bad (but probably not fatal) shock. But that's AC, and with AC a shock feels a lot worse than with DC My bike is DC, and Wikipedia says I'd barely feel 5ma DC, and my worst case, as per my measurement, is 1ma. So I don't really want the bike to fall into a canal, but even if it did, I wouldn't perish from electric shock.

Although the cold would probably do for me.

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