Help an idiot learn electrics...
Discussion
I'm trying to get a proper, real working understanding of electrics. In small words. Like you'd explain it to a small child.
I've tried looking for a good water analogy and the best thing i can find so far is...
Voltage: amount of potential push such as the height drop from a waterfall
Current: the width of the channel or pipe water can run through
Am i even close or is this b
ks?
I've tried looking for a good water analogy and the best thing i can find so far is...
Voltage: amount of potential push such as the height drop from a waterfall
Current: the width of the channel or pipe water can run through
Am i even close or is this b
ks?OK on the voltage analogy. Current is the rate of flow of the water -gallons per minute sort of thing.
The diameter of the pipe would equate to resistance in the circuit. - the lower the diameter the greater the resistance.
So for a given height of water (voltage) the rate of flow (current) is determined by the diameter of the pipe it goes through (resistance) which all comes together in ohms law -remember that?
What are you trying to learn? Automotive, home or just general? There are lots of online learning resources or you could go down the batteries, bulbs, wires and switches made from drawing pins and paper clips if you want to be more hands-on.
The diameter of the pipe would equate to resistance in the circuit. - the lower the diameter the greater the resistance.
So for a given height of water (voltage) the rate of flow (current) is determined by the diameter of the pipe it goes through (resistance) which all comes together in ohms law -remember that?
What are you trying to learn? Automotive, home or just general? There are lots of online learning resources or you could go down the batteries, bulbs, wires and switches made from drawing pins and paper clips if you want to be more hands-on.
A good way to imagine it is a tap. The voltage is the water pressure from the supply. It is a force, hence the term EMF (electro motive force). The resistance is the restriction from the valve in the tap, and the current is the intensity at which the water flows from the tap (hence current being abbreviated to I for intensity).
If you have the tap wide open (low resistance) you can expect a high intensity flow.
If you close the tap a bit (higher resistance) the intensity of flow will decrease.
You can also vary the pressure/voltage to affect the flow rate.
A good practical example of this is if you were to put a wire across a car battery terminals, the wire would very quickly melt as the low resistance would cause a massive current flow (hopefully before the battery exploded).
Also worth noting that the lower the voltage, the higher the current needs to be to provide the same
power output. This is why grid lines use huge voltages - the current drawn is relatively low and means smaller conductors can be used. Take a look at 25kV railway overhead lines, the stuff originally energised at 1,500v DC has massive conductors!
If you have the tap wide open (low resistance) you can expect a high intensity flow.
If you close the tap a bit (higher resistance) the intensity of flow will decrease.
You can also vary the pressure/voltage to affect the flow rate.
A good practical example of this is if you were to put a wire across a car battery terminals, the wire would very quickly melt as the low resistance would cause a massive current flow (hopefully before the battery exploded).
Also worth noting that the lower the voltage, the higher the current needs to be to provide the same
power output. This is why grid lines use huge voltages - the current drawn is relatively low and means smaller conductors can be used. Take a look at 25kV railway overhead lines, the stuff originally energised at 1,500v DC has massive conductors!
The Vindaloo Analogy
Voltage = The number of chillies
Current = The strength of chillies
Resistance = How cast iron your stomach is
Lots of voltage and current with no resistance means the st really flows.
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Silly analogies aside if you really want to know what is happening inside the wires then the term to google for is 'electron flow'. This BBC article has some useful graphics to help understand. - http://www.bbc.co.uk/science/robots/techlab/judder...
Electron - This can be thought of as the little spinny bit on the outside of an atom - http://www.ducksters.com/science/atom.gif
Copper Wire - Like most conducting materials, the atoms in a copper wire are arranged in a lattice structure. When you turn the ignition on in your car, what is happening is that electrons are jumping from one atom to the next along this lattice of atoms.
Current - The speed at which electrons jump along the lattice of copper atoms in a wire.
Resistance - When the electrons reach the starter motor they can not move so fast because instead of just trundling along the wire they have to do some work, ie turning the motor round.
Voltage - You've probably noticed the battery in your car has two components such as lead/acid. When charged, the lead has too many electrons and wants to get rid of them, while the acid hasn't got enough electrons and wants more of them. Voltage is the difference between how many electrons the lead wants to give off vs how many electrons the acid wants to absorb.
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As Max_Torque says, it's good to start with the most basic equation and work from there, however a working knowledge of the chemistry outlined above is useful for visualising a hybrid or electric car in an almost mechanical way, with electrons moving about and doing work just as pistons move about and do work in a conventional engine.
Voltage = The number of chillies
Current = The strength of chillies
Resistance = How cast iron your stomach is
Lots of voltage and current with no resistance means the s
t really flows.<><><><><><><><><>
Silly analogies aside if you really want to know what is happening inside the wires then the term to google for is 'electron flow'. This BBC article has some useful graphics to help understand. - http://www.bbc.co.uk/science/robots/techlab/judder...
Electron - This can be thought of as the little spinny bit on the outside of an atom - http://www.ducksters.com/science/atom.gif
Copper Wire - Like most conducting materials, the atoms in a copper wire are arranged in a lattice structure. When you turn the ignition on in your car, what is happening is that electrons are jumping from one atom to the next along this lattice of atoms.
Current - The speed at which electrons jump along the lattice of copper atoms in a wire.
Resistance - When the electrons reach the starter motor they can not move so fast because instead of just trundling along the wire they have to do some work, ie turning the motor round.
Voltage - You've probably noticed the battery in your car has two components such as lead/acid. When charged, the lead has too many electrons and wants to get rid of them, while the acid hasn't got enough electrons and wants more of them. Voltage is the difference between how many electrons the lead wants to give off vs how many electrons the acid wants to absorb.
<><><><><><><><><>
As Max_Torque says, it's good to start with the most basic equation and work from there, however a working knowledge of the chemistry outlined above is useful for visualising a hybrid or electric car in an almost mechanical way, with electrons moving about and doing work just as pistons move about and do work in a conventional engine.
ash73 said:
The electrons drift very slowly along a wire, the current is transmitted via electromagnetic (zero mass) interaction which propagates at c. Maybe think of it as waves on the water, rather than the flow of water itself?
I never quite understood this in physics lessons. Electrons drift very slowly, yet when you flick a switch everything is instant. What does the electromagnetic interaction do to create a current? I know if you coil a wire you can basically make an electromagnet when the current is flowing, but I always thought that a current created electromagnetic force, not the other way round?Sorry for thread hijack by the way...
CB2152 said:
ash73 said:
The electrons drift very slowly along a wire, the current is transmitted via electromagnetic (zero mass) interaction which propagates at c. Maybe think of it as waves on the water, rather than the flow of water itself?
I never quite understood this in physics lessons. Electrons drift very slowly, yet when you flick a switch everything is instant. What does the electromagnetic interaction do to create a current? I know if you coil a wire you can basically make an electromagnet when the current is flowing, but I always thought that a current created electromagnetic force, not the other way round?Sorry for thread hijack by the way...
However, having said that, imagine a hollow horizontal tube completely full of snooker balls. Now push an extra ball into one end, and almost immediately, one falls out the other end, but the original ball has only moved a short distance. Keep repeating that, and eventually the orginally added ball falls out the far end.
VinceFox said:
That's more the sort of level i need to start with.
It is a fantastic book. Lots of stuff the H&S types would gasp at! Pulling batteries apart etc. No theory, just learning by doing. It is a bit like the lectures on the telly at Christmas for kids.www.amazon.co.uk/gp/offer-listing/072140118X/ref=s...
Max_Torque said:
As i said, all these analogies are great if you're 3, but for anyone older, it's better to try and understand the basic physics and maths behind the science, rather than wrap it all up in another layer of abstraction imo!!
However, having said that, imagine a hollow horizontal tube completely full of snooker balls. Now push an extra ball into one end, and almost immediately, one falls out the other end, but the original ball has only moved a short distance. Keep repeating that, and eventually the orginally added ball falls out the far end.
Excellent. I pretty much get the formulae to a certain level (when I remember them) it's just things like that which used to confuse me. Hence why I did quite badly in A-level physics However, having said that, imagine a hollow horizontal tube completely full of snooker balls. Now push an extra ball into one end, and almost immediately, one falls out the other end, but the original ball has only moved a short distance. Keep repeating that, and eventually the orginally added ball falls out the far end.
That makes more sense now though, thanks!
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