This is a demo I did with a fairly small gauge wire with a 12 volt battery to show the effects of the resistance. This was probably my only chance to mess around with a 12v battery this large, so I took the opportunity and did this simple demo. I don't have a dc ammeter, so I could not show the amperage values. The size of the sparks could be seen, though.
The point of this video is to show how much less current can flow through 16 feet of 20 gauge (awg) wire, than a foot and a half of 8 gauge wire. Also, the more negative effect it can have is that it may become part of the load on the circuit, instead of just a conductor, and will not support enough current to pop the protection device (fuse/circuit breaker)
The reason people say you can get shocked from a car battery is because of a coil's tendency to have a voltage spike when it's disconnected. In my college class we used an oscilloscope and measured just that. The spike reached 51 volts, capable of shocking but not likely since you'd have to be touching the positive side near a coil.
3 мар 2013
