I'm confused about some electricity/magnetism things?

Question

Can someone please explain to me the differences between the following things? (by the way- it's not for homework, I just want to know)

-watts

-volts

-jueles (spelling?)

-ohms

-amperes

-anything else like that

Also, whats the difference between power and energy? I know one has something to do with time...

Thanks

Answer 1

watts are a measure of electrical power consumed.

Volts and Amperes are very similar.  If you think of electricity  as water coming out of a faucet then you can equate volts to the pressure behind the water and amperes to the amount of water itself.  Volts and amps together make up electrical power or watts by the West ViginiA formual

Watts = Volts x Amps

Joules is simply a unit of energy be it electrical, chemical, kinetic.  It's very small.

Ohms are a measure of resistance to electrical conductivity.  All materials have a certain ohms resistance.  Good conductors have extremely small ohms where others have more.  Sometimes more is desired if you want to limit the amount of electricity flowing through something.  Resistors are measured in ohms.

Energy is simply that energy where as power is work done by energy. usually over time or distance.

Answer 2

for the easy ones, let's compare it to water.

volts is like pressure.  higher pressure is higher volts

amps is like volume.  more water is more amps.

ohms is like a screen that water has to flow through.

as trash collects in the screen, and water has a harder time flowing through, it's like higher ohms.

to make a light bulb light, you need the proper resistance in the filament so that it will get hot, but not burn out.

too little resistance, and too much electricity will flow, and the bulb will burn out.

too much resistance and the filament won't get hot enough to light anything.

watts is volts*amps, is power.

10 amps * 10 volts - 100 volts * 1 amp = 100 amps * 1 volt.

sort of, you could turn a water wheel with a small amount of water, if it was going really fast, but if the water was going real slow, you'd have to have a really big paddle to get the same amount of energy from it.

if we go back to the light bulb example, let's consider a flash light bulb that is the same brightness as a ceiling bulb.   the bulb of a flash light is thicker -- has less resistance -- than the bulb in the ceiling.  because the voltage is so low, it's harder to make the filiment glow, so it takes more electrons, and to get more through, the resistance has to be lower.

the ceiling light on the other hand sees higher pressure, so the filament can be smaller, with higher resistance.  being smaller, it heats up faster, and doesn't take as many electrons.

where you see this in real life is in those high electrical wires.

it's like they have a little current, but really high pressure.

and at each end, there are transformers that change from high voltage low amps to lower voltage and more amps.

in your house, it just doesn't make sense to have electricity at 100,000 volts to run your frig.

joules is work.  that is power applied over a length of time.

Answer 3

To understand electrical terminology you first need to understand what electricity is. The word electricity is derived from the atomic particle the ELECTRON. All matter is made up of atoms containing protons,neutrons and electrons. Protons and neutrons make up the central nucleus their quantities determine the actual element and the electrons are said to orbit the nucleus similar to planets orbiting the sun (Simplified version of atomic structure). Electrons are present in all materials, in some materials the electrons can move relatively easily (they flow) through the material much like water through a pipe when an electrical force is applied (EMF electromotive force), this force is known as Voltage. These materials are said to conduct electricity easily and are good conductors which have low resistance. Other materials that have atoms with a different number of protons, neutrons and electrons have a high resistance and it is difficult to push the electrons through that material they are known as good insulators. This ability to conduct electrons is known as resistance and is measured in ohms. Low value ohms = good conductor (say copper) high value ohms =  good insulator (say PVC). Hence electrical cable is commonly a combination of copper conductor and PVC insulation.

The movement of electrons is called electric current and is measured in Amperes (A) and is the number of electrons flowing at any one time in a circuit. In fact when 6241500000000000000 electrons are flowing this = 1 ampere of electrical current. The symbol for current used is I because in the early scientific days before the understanding of atomic structure electric current was known as electrical Intensity.  

Voltage is the pressure to push the electrons through the circuit IE

A 6 volt battery will push twice as many electrons as a 3V battery through the same circuit.

So to summarise so far :-  Volts are the push, Amps are the flow and Ohms are the resistance to flow.

The instantaneous amount of electrical work that can be done is measured in Watts Eg 100 Watt light bulb, 8 Kilowatt shower, 10Kw motor etc. This can be likened to how powerful is a car, a person. an explosion etc. To determine the energy consumed we must measure how long (hours) the power (Kw) has been applied hence a 1000 Watt heater (1Kw)  for 3 hours would consume 3 Kilowatt Hours (KWH) in energy. This KWH is the basic unit of electricity charged on a UK electricity bill.

Joules (j) are the SI measurement of energy and applies to heat electricity and mechanical energy.  

1 J = 1 Newton metre = 1 Watt per second

Therfore 1KWH = 3.6 MJ