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Another Jeopardy Primer


Terence McCann
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Units of measurement:

To measure electrical quantities, certain definitions have been adopted. Charge is a measurement in coulombs © and represented by q in equations. One coulomb is equal to 6.5 X 1018 electrons (or protons). Current, the flow of charge, is measured in amperes (A) and represented by i or I in equations. One ampere represents one coulomb of charge flowing past a point in one second and so amperes can also be expressed as coulombs per second. Electromotive force is measured in volts (V) and represented by e, E, v or V in equations. One volt is defined as the electromotive force between two points required to cause one ampere of current to do one joule (measured as energy) of work in flowing between two points. Voltage can also be expressed as joules per coulomb.

And that's the rest of the story.

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Units of measurement:

To measure electrical quantities, certain definitions have been adopted. Charge is a measurement in coulombs © and represented by q in equations. One coulomb is equal to 6.5 X 1018 electrons (or protons). Current, the flow of charge, is measured in amperes (A) and represented by i or I in equations. One ampere represents one coulomb of charge flowing past a point in one second and so amperes can also be expressed as coulombs per second. Electromotive force is measured in volts (V) and represented by e, E, v or V in equations. One volt is defined as the electromotive force between two points required to cause one ampere of current to do one joule (measured as energy) of work in flowing between two points. Voltage can also be expressed as joules per coulomb.

And that's the rest of the story.

Is this "in your experience," or do you have a specific reference to back it up?

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Units of measurement:

To measure electrical quantities, certain definitions have been adopted. Charge is a measurement in coulombs © and represented by q in equations. One coulomb is equal to 6.5 X 1018 electrons (or protons). Current, the flow of charge, is measured in amperes (A) and represented by i or I in equations. One ampere represents one coulomb of charge flowing past a point in one second and so amperes can also be expressed as coulombs per second. Electromotive force is measured in volts (V) and represented by e, E, v or V in equations. One volt is defined as the electromotive force between two points required to cause one ampere of current to do one joule (measured as energy) of work in flowing between two points. Voltage can also be expressed as joules per coulomb.

And that's the rest of the story.

Is this "in your experience," or do you have a specific reference to back it up?

Lol... wise guy [;)] My name is McCann, not Volta (although I wish it were Warren Buffett Jr.)

The ARRL Handbook 2010, hardbound edition, Chapter 2 page 2.2.

All kidding aside I think it's important to know how certain things work to see big picture.

Believe it or not I do a lot more reading than posting.

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Units of measurement:

To measure electrical quantities, certain definitions have been adopted. Charge is a measurement in coulombs © and represented by q in equations. One coulomb is equal to 6.5 X 1018 electrons (or protons). Current, the flow of charge, is measured in amperes (A) and represented by i or I in equations. One ampere represents one coulomb of charge flowing past a point in one second and so amperes can also be expressed as coulombs per second. Electromotive force is measured in volts (V) and represented by e, E, v or V in equations. One volt is defined as the electromotive force between two points required to cause one ampere of current to do one joule (measured as energy) of work in flowing between two points. Voltage can also be expressed as joules per coulomb.

And that's the rest of the story.

Reminds me of the first day of Circuits 1 class back in my freshman year of college.

I do hear a lot of people (including some home inspectors) say that "current flows in a circuit" which is not accurate. "Current" is actually the movement of something like "a river's current". Charge is what actually flows in an electrical circuit. Just saying..

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Units of measurement:

To measure electrical quantities, certain definitions have been adopted. Charge is a measurement in coulombs © and represented by q in equations. One coulomb is equal to 6.5 X 1018 electrons (or protons). Current, the flow of charge, is measured in amperes (A) and represented by i or I in equations. One ampere represents one coulomb of charge flowing past a point in one second and so amperes can also be expressed as coulombs per second. Electromotive force is measured in volts (V) and represented by e, E, v or V in equations. One volt is defined as the electromotive force between two points required to cause one ampere of current to do one joule (measured as energy) of work in flowing between two points. Voltage can also be expressed as joules per coulomb.

And that's the rest of the story.

Reminds me of the first day of Circuits 1 class back in my freshman year of college.

I do hear a lot of people (including some home inspectors) say that "current flows in a circuit" which is not accurate. "Current" is actually the movement of something like "a river's current". Charge is what actually flows in an electrical circuit. Just saying..

Isn't that what it is saying though? I'm not sure if you agree with the wording or disagree.

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One volt is defined as the electromotive force between two points required to cause one ampere of current to do one joule (measured as energy) of work in flowing between two points.

Close but no cigar. One volt is the electromotive force required to create a current of one ampere through a resistance of one ohm. It results in the dissipation of 1 watt of power.

Marc

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One volt is defined as the electromotive force between two points required to cause one ampere of current to do one joule (measured as energy) of work in flowing between two points.

Close but no cigar. One volt is the electromotive force required to create a current of one ampere through a resistance of one ohm. It results in the dissipation of 1 watt of power.

Marc

Marc, I agree, although you should mention 'time' in your equation.

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When I read your post, I felt that 'time' should be included in your definition. But it is yours singular. I don’t mean anything other then trying to add.

My definition of an ampere ‘is a measure of an electric charge passing a point per unit time.’ So as to help in further qualifying your definition. Or I go back to the hockey game, and shut up.

mongo

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One volt is defined as the electromotive force between two points required to cause one ampere of current to do one joule (measured as energy) of work in flowing between two points.

Close but no cigar. One volt is the electromotive force required to create a current of one ampere through a resistance of one ohm. It results in the dissipation of 1 watt of power.

Marc

When you transport one joule of energy through a channel every second, the flow-rate of energy is 1 Joule/Sec, and "one Joule per second" means "one watt."

Perhaps your not familiar with the term Joule.

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