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Coulombs of charge

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e44-72

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Hello

Just wanted to know the answer to this question.

I know current always flow from positve to negative and as electrons are negatively charge they flow in the opposite direction (negative to postive). And that 1Q of charge is the amount of charge tranported by 1A in 1sec of time and they are 6.241506×10^18 electrons in 1Q of charge.

So therefor if current is the transport of charges (a number of electrons) do coulombs of charge flow from negative to positive around a circuit like electrons?

Thank you for reading and any replies
 
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Thank you ericgibbs for the website link, its very useful. I wanted to ask whether a measurement in coulombs has to be defined as negative of positive. For example is 2Q of charge where transported and electrons where the charge carriers would have to write -2Q of charge or is it simply just 2Q?
I am getting confused mathematically:
1 electron (1e) = -1.6x10^-19 Coulombs of charge, therefor
6.241506×10^18 electrons = (-1.6x10^-19) x (6.241506×10^18) coulombs which = -0.9986...Q or -1Q
but 6.241506×10^18 electrons should = +1Q not -1Q, so how can this be?
 
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Hi e44,
Coulomb do not exist. What exists is electrons. Coulomb do not flow; electrons do.
The charge on each electron is transferred along the conductor when current is flowing. The amount of charge which has flowed is the charge constant times the number of electrons. Your understanding of the definition of 'coulomb' is correct.
I think you confuse the electron having a charge and having some mass, with the measure of the total charge which is given in coulomb. So, the electrons flow from negative to positive but the total charge is the product of 'electronic charge times the number of electrons'.
Have I understood your question?
Do you want to ask something more?
 
Thank you rumpfy, you have understood my question and you have helped me understand where i'm getting confussed. The only other thing I wish to clarify is whether a mearment in coulombs is always a positive number or can it be a positve/negative number for example is the charge of an electron in coloumbs -1.6x10^-19 or just 1.6x10^-19?
In other words what I am saying is if the charge carriers are negative does the measurement of there charge have to be givern as a -amount of coulombs such as -2Q of charge?
 
Coulomb measurement is in the same direction of conventional current. I used this technique to measure extremely low currents using an electrometer from www,Keithley.com which has a Coulomb mode. Under program control, I would turn off zero check, zero the meter and wait 30 sc and then take a measurement. Couloumbs/30 s would be the number of Amps. The meter could be showing pC or nC or uC etc. I was interested in currents <2 pA.
 
e44-72,

I know current always flow from positve to negative and as electrons are negatively charge they flow in the opposite direction (negative to postive).

No, charge flows, current does not. The term "current flow" means "charge flow flow". Current exists, but it does not flow twice. The current direction depends on its polarity and voltage polarity. Holes and protons will flow in an opposite direction with respect to electrons.

And that 1Q of charge is the amount of charge tranported by 1A in 1sec of time and they are 6.241506×10^18 electrons in 1Q of charge

A coulomb is abbreviated by "C", not "Q". A coulomb is simply a defined number of charges (positive or negative) of which you already know the value. A electron contains the smallest basic unit of negative charge, a proton contains the smallest basic unit of positive charge. There are no fractional charges.

So therefor if current is the transport of charges (a number of electrons) do coulombs of charge flow from negative to positive around a circuit like electrons?

Current (amperes) is the number of charge carriers (coulombs) moving per time (seconds). The direction depends on the polarity of the charge and the voltage polarity.

Ratch
 
Electronic charge is a fundamental physical parameter just like the speed of light, for example.
In the study of static electricity, there is the concept of 'Free Electrons'.
These are separate charges which move about without being bound to a nucleus. The charge is a magnitude only; it has no positive or negative per se, but with respect to the nucleus of an atom, the electronic charge is opposite to the charge of the protons in the nucleus.
It is important to remember that with moving electrons there is a current. The direction of the current is positive if one way into a terminal, or negative if the opposite way. You need to understand that with 'charge' and 'current', the charge is a magnitude only.
I have a beautiful old book called 'Principles of Electricity and Magnetism'. It was written in 1949 by Professor Harnwell of the Pennsylvania University. There are many other books too, but I have this one which I bought at a fair in 1978.
You might try to get a similar book.
Good luck with your study.
Hope you are satisfied with my answers.
 
Thank you for your help and answers, This is they way I understand things, correct me if I'm wrong:
If there was a basic circuit, battery and light bulb and there was 2A of current and was on for 10sec.
C (charge) = A (amps) x T (time) so 2 x 10 = 20C of charge have flown round the circuit.
In terms of electrons -20C worth of charge have gone from negative to positive but therefor 20C worth of positive charge will have gone from positive to negative round the circuit.
Is this a correct understanding?

Thank you for your help and thank you rumpfy for the book suggestion, I'll look into getting it.
 
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e44-72,

In terms of electrons -20C worth of charge have gone from negative to positive but therefor 20C worth of positive charge will have gone from positive to negative round the circuit.
Is this a correct understanding?

For electric circuits with metal wires, you are right. Negative electrons are the charge carriers in this case. There are no positive charge carriers in wires, and no current consisting of positive charge current exists. For positive charge carriers, think of positive ions in electrochemistry, and p-type semiconductor material.

Ratch
 
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