There’s probably books out there but generally you work to the IEE regulations (currently) 18th edition. But that doesn’t really teach you anything beyond what you can and can’t do legally. It’s one of those things where a little bit of knowledge is dangerous.Thanks
Basic DIY questions?
- Thread starter UnderOpenSky
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existentialist
Tired and unemotional
While I wouldn't dispute the truth of that, it is a simplification which can lead to some dangerous assumptions
Nobody's suggesting that this be done. I think you're in danger of tilting the fact:red herring balance a little, here.
I just want to know how to do basic maths with volts or amps or whateverthefuck - or even properly understand what they are in a way that doesn't go in one ear and straight out the other - and have some idea of why you can connect thingamajig A to doodads X or Y but thingamajig B needs to be connected to a whatchamacallit or else the whole lot will go bang...
WouldBe
Dislicksick
That only applies to mains wiring so would be no help with a battery powered electric fence.
I thought that is what he was asking.
I thought the question was wider than that?
WouldBe
Dislicksick
It all depends what you want to do with those. Just from volts and amps you can work out watts by multiplying them together or the resistance of the circuit by dividing volts by amps.
Electronics is a large subject. Without knowing what the various thingamajigs, doodads and whatchamacallits are it's impossible to say.
Batteries are ultra low voltage* dc current. Mains is low voltage alternating current.
*actually not all so I’ll shut up.
WouldBe
Dislicksick
Mains powered would be dangerous. If a fault occurred the fence could become live and result in a fatal electric shock.
Electricity does behave basically the same wether it's from a battery or the mains. Mains is more complex as you have to take into account the frequency and any impedance problems that may result.
WouldBe
Dislicksick
It is but the IEE regs only really apply to mains circuits.
I’ve no idea about electric fences but what is recharging the batteries? Or does someone change the batteries giving the cows a window to escape?
I thought they wanted an understating of electrics beyond the scope of a battery powered fence.
existentialist
Tired and unemotional
This is a little way outside my wheelhouse, but - switched-mode PSUs? I'm not sure if they are free floating, as they don't necessarily use a transformer which isolates the low-power side from the mains side.
WouldBe
Dislicksick
They are charged separately. Usually the farmer has a spare battery already charged so they can easily swap them out without leaving an escape route.
existentialist
Tired and unemotional
You'd do worse than to start with a basic electrical teach, something that starts by explaining Ohm's Law, for example.
Fair enough. So the charging of the batteries does involve mains electricity.
existentialist
Tired and unemotional
Quite possibly, but the point is that the supply to the fence itself would be completely isolated from the mains supply. Barring failure modes, and even those can be accounted for with suitable safety tech (and residual current protection on the mains side).
WouldBe
Dislicksick
They don't use transformers either. Transformers have isolated windings so the output is floating in relation to the mains .
existentialist
Tired and unemotional
Yes, that's what I was getting at
I don’t know of an instance where a failed transformer delivers the voltage prior to being stepped down.
Presumably the energiser would stop that, idk.
Like I said, forget about the electric fence anyway.
I literally have no idea what any of this means. I assume everyone here has better things to do with their time than type out explanations to my twenty billion stupid questions, so I was just asking on the off chance that someone might go "yeah, here's a really great website/book/whatever that explains all this shit right from the very basics"
But never mind
College really.Presumably the energiser would stop that, idk.
Like I said, forget about the electric fence anyway.
I literally have no idea what any of this means. I assume everyone here has better things to do with their time than type out explanations to my twenty billion stupid questions, so I was just asking on the off chance that someone might go "yeah, here's a really great website/book/whatever that explains all this shit right from the very basics"
But never mind
WouldBe
Dislicksick
Electrics or electronics?
IEEE regs specify things like cable sizes depending on current, cable length, how it's fixed . It's basically a load of tables and rules that you need to work to.
Which is what I said. There’s a section in there on farms.
StoneRoad
heckling from the back!
That's the theory - but a few years ago around here [SW Northumberland] some "clever" toe-rags went on a battery nicking spree.
Quite a few tractors and electric fences were tampered with over a relatively short period of time ... and several lots of beasts got out from where they should have been.
Luckily, when the ejits then went to a scrappie to sell their spoils, one of the batteries they offered up was sufficiently distinctive & known to the scrappie, that he got the poliss to call while faffing around weighing & calculating ...
WouldBe
Dislicksick
Basically
Voltage is like water pressure.
Current is like the flow rate. A larger pipe can 'carry' a larger flow of water just like a larger cable can carry more current.
Watts is a measure of power.
DC means the power flows in one direction only like from a battery.
AC the power flow alternates flowing from live to neutral for half the time and from neutral to live for the other half.
Frequency is basically how many times a second the flow changes direction.
Resistance is what it says it is. It's a resistance to direct current flow. Something that has a low resistance allows a larger current to flow.
Impedance is the resistance to an AC current.
WouldBe
Dislicksick
There should also be a section on outside circuits. It will have very little in it to do with electronics.
teuchter
je suis teuchter
I'd actually specifically recommend NOT to try and learn any of this by asking questions on internet forums, because there are certain things which people tend to get into arguments about, which really don't matter if you are just trying to get your head around the basics. I think the reason for this is that there are various analogies you can use to understand what's going on with electricity - imagining it as a flow of water is the most common one - and these analogies are for most purposes very helpful for understanding things up to a useful level, but start to fall apart on certain details or if you try and extrapolate them too far. I'd recommend using some conventional type textbooks, or online resources aimed at "beginners" and save the online discussions for later, if and when you get deeper into any of it.
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