Historically, what came first: coulomb unit or ampere unit?

In summary, the conversation discusses the historical order of the coulomb and ampere units. It is mentioned that the first charge and current units were not part of the SI system. The ampere was chosen before the coulomb was defined as 1 amp-second. The conversation also touches on the change in the definition of the ampere to one tenth of the "absolute ampere." The speaker expresses their interest in finding out who and when this change was made. They also mention that keeping the ampere equal to the abampere would make more sense in the SI system.
  • #1
HECOLACO
2
0
Historically, what came first: coulomb unit or ampere unit?
 
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  • #2
This is a bit murky, because the first charge and current units weren't SI.
If you mean the SI coulomb and ampere, then I believe the ampere was chosen, and then the coulomb defined as 1 amp-sec. At some point, the ampere was chosen to be one tenth of the "absolute ampere" (now called the abampere in the electromagnetic unit system), probably becaause some engineer thought the absolute ampere was too large a unit.
I have been trying myself for some time to find out who and when this change was made. (It was sometime in the 19th century.) SI units would make more sense if if the ampere had been kept equal to the abampere. Then, in cgs, mu0/4pi would equal 1.
 
  • #3
Thank you for your attention, Meir.
 

1. What is the difference between coulomb and ampere units?

Coulomb and ampere are both units of measurement used to quantify the amount of electric charge. Coulomb is a unit of electric charge, while ampere is a unit of electric current. One coulomb is equal to the amount of charge that passes through a conductor in one second when the current is one ampere.

2. Which unit came first, coulomb or ampere?

The ampere unit was established in 1881 by the International Electrical Congress, while the coulomb unit was defined in 1946 by the General Conference on Weights and Measures. Therefore, the ampere unit came first.

3. Why were these units created?

These units were created to standardize the measurement of electricity and make it easier to compare and communicate measurements across different systems and countries.

4. Are these units still used today?

Yes, both the coulomb and ampere units are still used today in various fields such as electrical engineering, physics, and chemistry.

5. Can these units be converted into each other?

Yes, these units can be converted into each other using the equation: 1 ampere = 1 coulomb per second. This means that one ampere is equal to one coulomb of charge passing through a conductor in one second.

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