Charge of an electron in Coulombs?

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SUMMARY

The charge of an electron is definitively -1.602176565(35) × 10-19 C. In electrical circuits, current is defined as the flow of positive charge, which explains why the current is considered positive even when electrons, which carry a negative charge, are the actual charge carriers. When calculating the number of electrons corresponding to a charge, such as 18 C, the formula used is the total charge divided by the magnitude of the electron charge, disregarding the negative sign. This approach clarifies that while electrons have a negative charge, the concept of current remains positive.

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  • Understanding of basic electrical concepts such as current and charge.
  • Familiarity with the formula I = Q / t for calculating current.
  • Knowledge of the significance of charge polarity in electrical circuits.
  • Basic mathematical skills for performing calculations involving Coulombs and electron charge.
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  • Learn about the historical context of charge carriers in electrical theory.
  • Explore the concept of charge conservation and its implications in circuit analysis.
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mosad655
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Is it correct that the charge of an electron in Coulombs is

- 1,602 176 565(35) • 10-19 C ?

By inserting this in the formula for current I = Q / t, that would make the current a negative number. I don't reckon having read about negative currents though. So what's the explanation for how the negative sign dissappears and currents end up always being positive?
 
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mosad655 said:
So what's the explanation for how the negative sign dissappears and currents end up always being positive?
Current is usually defined as flowing in the direction of positive charge carriers. (Historically, it wasn't anticipated that the charge carriers in a wire, for instance, were actually negatively charged.) So if electrons move to the right, the current is defined as moving to the left.
 
but is it correct that the charge of an electron in Coulombs is - 1,602 176 565(35) • 10^-19 ?
 
mosad655 said:
but is it correct that the charge of an electron in Coulombs is - 1,602 176 565(35) • 10^-19 ?
Sure.
 
so let's say.. 18 C would be then be 18 / (- 1,602 176 565(35) • 10^(-19)) electrons? That's a negative number, how is it possible to have a negative number of electons?
 
mosad655 said:
so let's say.. 18 C would be then be 18 / (- 1,602 176 565(35) • 10^(-19)) electrons? That's a negative number, how is it possible to have a negative number of electons?
What's 18 C? Obviously not the charge on a bunch of electrons. Realize that if something ordinarily neutral is missing a number of electrons, that it will have a positive charge.

What problem are you trying to solve?
 
In the textbook that I have, it comes with this example:

A 5 amp current flows for an hour. The total charge that passes by in such case, is Q = I • t = 5 A • 3600 s = 18000 C or 18000 Coulombs. Now how many electrons is that?
 
mosad655 said:
In the textbook that I have, it comes with this example:

A 5 amp current flows for an hour. The total charge that passes by in such case, is Q = I • t = 5 A • 3600 s = 18000 C or 18000 Coulombs. Now how many electrons is that?
Just divide by the magnitude of the electron charge. Don't get hung up with signs.
 
So coulomb is not the unit for charge, but the unit for the magnitude of charge?
 
  • #10
mosad655 said:
So coulomb is not the unit for charge, but the unit for the magnitude of charge?
You can think of it that way. That's why the charge on the electron is a negative number of Coulombs.
 

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