You can’t see it, you can’t hear, you can’t smell it, you can’t taste it but when you touch it – you know it’s there. Electricity. Its funny stuff I don’t think I’ll ever understand in a month of Sundays. But, the experts say you need to know some basics before you can begin any mucking around with car electrics. Yeah, well, that’s what the experts say, but being a bloke, I haven’t got time to learn all that stuff properly so I just learn enough to get started. Which, to be fair, isn’t really enough to get started.
I’ve heard of volts, amps and watts (named after Scottish inventor James Watt). I once had a job soldering electronic bits to electronic circuit boards so I’d heard of capacitors and resistors but I didn’t really know what any of these things did or meant. I think Watts is a measure of power (Scottish influence no doubt). And Power is voltage multiplied by current. I think current is measured in amps. Volts must be measured in …um…. Volts? Or is volts a measure of current? So what does that make an amp? I dunno. I could look it up to help me write this bit, but then that would be cheating wouldn’t it?
Hang on a minute…….. By typing this I think I’ve worked it out. Amps is a measure of resistance, as in a 13 amp fuse. So 12 volts, as in a car battery voltage, multiplied by, say, a 5 amp cable would allow you to power a 60 Watt thing – like a 60 Watt light bulb. A 1200 watt hairdryer, on the other hand, would require a 100 amp cable, which I think is about as thick as the Titanic’s anchor chain. Sorry Sarah, not sure I’ll be able to wire up a 12 volt hair dryer socket for you going by this maths.
Clearly I needed a lesson on how car electrics really work….. With the internet as my teacher many hours later I’d figured out some basics. It goes like this. Electricity is made up of electrons and other tiny things you can’t see and they all live in your car battery which is split into two halves. A positive side and a negative side. Or Live and Ground. Oddly, the ones on the positive side would like to live on the negative side – the grass is always greener and all that. The problem is how do the positive electrons get from one side to the other. The solution is to connect each side with wire cables and then the electrons will use this connection to run from the positive side to the negative side as quick as they can.
Try this at experiment at home: using a thick spanner, lay it on top of your battery so it touches the positive and negative sides and then see what happens.
No don’t do that. Please don’t.
Now get this. The thickness of a cable controls how much electricity can travel down it in one go. If the wire cable is too thin then it will get hot because all the electrons are trying to squeeze down what is actually a small corridor. And if the wire gets too hot it can melt and break. This is how a Fuse works. It will melt and break if too many electrons try to run through it all at once. Still with me? A thick spanner, by the way, has got a lot of capacity to carry electricity. Even 12 volt electricity. So unless you are a spanner, then don’t try the spanner experiment. But if you do, please youtube it.
Given electrons will run from one side of the battery to another automatically you may as well get them to do stuff on the way round, like run through a light bulb which has tiny thin wires that get really hot but not so hot that they melt. And when these tiny wires get hot they go all bright – just like a light. Which also explains why light bulbs also get hot. How simple and how magic is that? The electrons also do other things like make your wipers wipe and make your horn sound like a clown’s squeezy nose. Put simply, electric circuits are just like an obstacle course for electrons to run around.
Once the electrons have done the things you’ve asked them to do you need make sure they can get to the negative side because without this final connection they won’t leave the positive side of the battery. They’re not fools you know. So, to complete the circuit all one needs to do is simply connect a wire from the last job, like the light bulb, onto any part of the bodywork. The bodywork, being made of metal will be used by the electrons to reach the neagtive side of the battery which is also connected to the bodywork. If you’re lost by now, don’t worry – I’m not sure I’ve kept up myself. Whatever, this means the bodywork of the bus has zillions of electrons rushing back to the battery all the time. We can’t see them, hear them, smell them, feel them or taste them. Although if you’re a bloke you’ve probably tasted electricity by sticking your tongue on the end of one of those 9 volt square batteries. It tastes uncomfortably tingly if memory serves me right. Girls – you should try it sometime. Go on, live a little.
There are also things called neutrons too. I don’t know what these things do. If anyone knows what a neutron is please leave a comment – then we could all learn something new. And if you’re feeling really clever perhaps you could explain electricity accurately rather than in the made up fashion of this waffle. But before you do, do the spanner test first to prove that I at least got that bit right.
Imagine you’re an electron and you’re itching to be let loose onto the circuit. Imagine how excited you must be feeling – remember you’re from the positive side of the battery. Oh man, I can’t wait to get out there and do some stuff! I hope I get to go through the radio, or into a sprak plug to help blow up the petrol to make the engine go. Or maybe I’ll get to dazzle on the full beam, or go through the crazy clown’s nose. Let me outta here – I got things to do. I’ve got so much energy to burn. Somebody turn something on – let’s do it man, let’s do it. ……..Imagine then how you must feel when you get back to the negative side of the battery……. Courtesy Light! Is that all I’m good for? A bloody courtesy light. I had potential you know! I had potential to be so much more! Courtesy light my arse…. No wonder they end up on the negative side