Voltage, Current, Resistance definitions

[mtanti]

Can someone please give a straight forward and easy to understand definition of the 3 mentioned phenomenone in terms of electrons if possible?
Thanks!

 

[chroot]

Voltage is directly related to the force electrons feel in a wire. This force propels them through the wire. You can think of voltage (more correctly expressed as a difference in electrical potential) as an analogy to water pressure in a pipe. The pressure is what causes water to flow out of your tap, for example.

Current is a measure of the number of electrons that pass through some given point in a wire per unit time. The larger the current, the more electrons flow through the wire per unit time.

Resistance is caused by a material's interaction with electrons. Some material inhibit electrons from moving quickly through them, in the same way that a sponge shoving into your water faucet would inhibit the flow of water.

- Warren

 

[mtanti]

So voltage is the amount of energy in each electron and current is the speed of the electrons whilst resistance is the multiple of speed reduced from the electrons?

 

[chroot]

Yes, voltage is related to the kinetic energy of each electron. An electron moving through a potential difference of 100 volts gains twice as much kinetic energy as an electron moving through a potential difference of 50 volts.

Current, however, is not related to speed. You can have a large number of very slow electrons passing some point in a wire, or a smaller number of very fast electrons, and the current will be the same. Keep in mind that the actual speed of electrons in wires -- the speed they move from one terminal of a battery to another, for example -- is quite slow. You should not worry much (at this point) about speed at all.

Resistance is not so much a process of slowing electrons down as it is a process of stripping them of kinetic energy and turning that energy into heat. Certainly, you can't reduce kinetic energy without reducing speed, but it's much simpler to view resistance as a phenomenon of energy rather than speed.

- Warren

 

[es1]

The traditional, easy to understand, definition involves the water analogy.
Here is a good presentation of it.
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/watcir.html

Please don't take it too far though. Once you have the inituitive understand change to thinking in energies, as chroot suggests.