Re: electrical units

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Mddeming-at-aol-dot-com 

In a message dated 2/3/04 10:53:51 PM Eastern Standard Time, 
tesla-at-pupman-dot-com writes:
One Ampere is one Coulomb of charge flowing past a point per second.

A volt is the EMF required to force one Ampere through one Ohm.

Now... was the Coulomb (6.25 x 10^18 electrons) defined first and if so how?

And the Ohm?

Tom L.

These were the popular definitions when I was in school:
A coulomb is that unit of charge which, when separated by a distance of one 
meter from a like quantity of charge, produces a force of one Newton.

The ESU (aka electrostatic unit, aka statcoulomb) is that quantity of 
charge which will repel a like quantity with a force of one dyne at a 
distance of one cm. ( 1 Coulomb=3x10^9 esu)

Volt = Joules/Coulomb One volt is the difference in potential resulting 
from expending one Joule of energy moving one coulomb of charge.

The absolute ampere was defined as the current that, when established in 
two infinitely long wires connected in series, placed parallel and one 
meter apart, produces a force of 2 x 10^-7 Newtons for each meter of 
circuit length. Prior to 1948, the international ampere was defined as that 
current which would deposit 1.1183 mg of silver from a standard silver 
solution in one second.  1 Ampere = 1 coulomb/sec.

Ohms = Volts / Amps The Ohm was defined as the resistance of a conductor 
carrying a current of one Ampere when the potential difference between its 
terminals is one volt.

Hope this helps,

Matt D.