Some devices that has only 1 wire! Eh?

Thread Starter

Lightfire

Joined Oct 5, 2010
690
Hello,

I looked at my dad's bicycle and saw that there is only 1 wire there! I mean the lamp in my dad's bicycle has only 1 wire! And I don't know how it is being lighted as there is no battery!:eek:

OK, general question. How does a lamp or any other devices that has only 1 wire will work?:cool:
 

magnet18

Joined Dec 22, 2010
1,227
It has 2 wires, one of them is just disguised as the frame of the bike itself :D
Since it's metal it can be used as the ground and save on wire.

It's probably powered by a device similar to a small generator powered by the spinning of the wheels or the pedals.
 

DerStrom8

Joined Feb 20, 2011
2,390
The "one wire" idea is not limited to bicycles, either. It is commonly used in motorcycles, cars, boats, and just about any other vehicle that has an electrical system. The "negative" is usually just the frame of the vehicle itself (except for a few automobiles that are positive-grounded, and the "positive" is the frame).
Der Strom
 
I tend to agree with all of what you've just said except for boats! With a fibre-glass hulls, there's no metal to provide the earth return and with metal hulls they avoid using the hull due to electrolytic corrosion. I remember sending my apprentice to pull the fuses for one circuit on a boat one day then hearing him swear as he caught a jolt. Sure enough he'd only pulled the live fuse and left the neutral fuse behind, leaving the neutral line floating at 120Vac WRT earth! (It was a 240Vac system).

Sometimes i must admit the frame/skid/chassis that something like an engine is in will be used as an earth return in a boat but only as the earth return for that particular item/assembly and it will be isolated from the ships hull for the reason stated above.

Hope this helps!
 
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