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electrical units





I believe historically there were at least six sets of electrical units

used. The original coulomb was an electrostatic unit the used coulombs law

and related the size of the (equal) charges on two sphere to the repulsive

forces between them at a distance of 1 cm separation.

there was a device appropriately called a coulombometer that was an

electroplating cell that counted the electric charges the deposited a

certain amount of silver by letting a current run through for a while and

massing the silver.

the amount of charge was fundamentaland the the rate of 1 C/s was defined

as the ampere.

after the magnetic effects were discovered it was determined that it

was easier to define the current by experiments that measured the forces

between two coils and the definitions were changed to make the ampere the

fundamental one.



Check old CRCHandbooks for esu, emu, coulomb, abcoulomb, statcoulomb, etc

Jim Braunsdorf