A measure of the rate at which electric charge is transported (especially through a circuit), it has units of charge/time.
Questions tagged [electric-current]
3477 questions
79
votes
11 answers
Why is the charge naming convention wrong?
I recently came to know about the Conventional Current vs. Electron Flow issue.
Doing some search I found that the reason for this is that Benjamin Franklin made a mistake when naming positive and negative charges.
There is even this little comic…
GetFree
- 1,321
78
votes
20 answers
Why doesn't current pass through a resistance if there is another path without resistance?
Why doesn't current pass through a resistance if there is another path without resistance? How does it know there is resistance on that path?
Some clarification:
I understand that some current will flow through the resistance.
A depiction of this…
ten1o
- 1,255
70
votes
3 answers
Why is the ampere a base unit and not the coulomb?
I always thought of current as the time derivative of charge, $\frac{dq}{dt}$. However, I found out recently that it is the ampere that is the base unit and not the coulomb. Why is this? It seems to me that charge can exist without current, but…
Greg
- 1,790
53
votes
14 answers
What *exactly* is electrical current, voltage, and resistance?
I am taking AP Physics right now (I'm a high school student) and we are learning about circuits, current, resistance, voltage, Ohm's Law, etc. I am looking for exact definitions of what current, voltage, and resistance are.
My teacher, as I'm sure…
Addison
- 645
52
votes
6 answers
Why is AC more "dangerous" than DC?
After going through several forums, I became more confused whether it is DC or AC that is more dangerous. In my text book, it is written that the peak value of AC is greater than that of DC, which is why it tends to be dangerous. Some people in…
Four Seasons
- 2,585
- 10
- 36
- 51
46
votes
11 answers
Birds on a wire (again) - how is it that birds feel no current? They are just making a parallel circuit, no?
I have been thinking about this and I know that other people have answered this on here, but there's one part that still baffles me, and it has to do with parallel circuits.
If I connect a battery to a resistor, and connect another in parallel to…
Jesse
- 939
45
votes
5 answers
Speed of light vs speed of electricity
If I arranged an experiment where light raced electricity what would be the results? Let's say a red laser is fired at the same time a switch is closed that applies 110 volts to a 12 gauge loop of copper wire with a meter at a distance of ten…
Lambda
- 4,753
42
votes
5 answers
Why is current a scalar quantity?
Current has both magnitude and direction. As per the definition of vector defined in encyclopedia, current should be a vector quantity. But, we know that current is a scalar quantity. What is the reason behind it?
user36159
- 421
- 1
- 4
- 3
41
votes
3 answers
Will the volt, ampere, ohm or other electrical units change on May 20th, 2019?
When watching a video by Veritasium about the SI units redefinition (5:29), a claim that the volt and unit of resistance (presumably the ohm) will change by about 1 part in 10 million caught my attention:
[...] I should point out that a volt will…
user231851
40
votes
9 answers
If electrons are identical and indistinguishable, how can we say current is the movement of electrons?
When we talk about current, we say electrons are "flowing" through a conductor. But if electrons are identical particles, how does it make sense to talk about them flowing?
To expand on that: imagine the simplest wire, just a 1-D chain of copper…
Mark Fugate
- 609
39
votes
8 answers
Is electricity really the flow of electrons or is it more involved?
I am new to the physics category of the Stack Exchange site. I apologize if my question is wrong, too broad, simple, or worded incorrectly. I am just trying to figure out what is true and false when it comes to electricity and its vast world. I want…
spiderman0297
- 509
39
votes
5 answers
If the Earth is a good conductor of electricity, why don't people get electrocuted every time they touch the Earth?
Since the Earth is a good conductor of electricity, is it safe to assume that any charge that flows down to the Earth must be redistributed into the Earth in and along all directions?
Does this also mean that if I release a million amperes of…
Swami
- 1,917
35
votes
3 answers
How does electricity propagate in a conductor?
On a systems level, I understand that as electrons are pushed into a wire, there is a net field and a net electron velocity. And I've read that the net electron drift is slow. But electricity travels through the wire, essentially at c, and I want…
Dov
- 1,035
33
votes
4 answers
How do electrons know which path to take in a circuit?
The current is maximum through those segments of a circuit that offer the least resistance. But how do electrons know beforehand that which path will resist their drift the least?
Swapnanil Saha
- 787
30
votes
10 answers
Is every open circuit a capacitor?
I think that even open-ended wires can let AC current flow through them, just with a low capacitance. I also think an antenna could be a capacitor and open ended. Am I thinking correctly?
Bálint Tatai
- 807