# Questions tagged [electric-current]

A measure of the rate at which electric charge is transported (especially through a circuit), it has units of charge/time.

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### Cells connected with reverse polarity in parallel

How exactly are the corresponding equations derived here?
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### Capacitors charging, resistance much more?

I am overwhelmed by the amount of doubts i am having regarding this device (CORRECT ME WHEREVER I AM WRONG PLEASE) First things first if we connect a capacitor using two ideal wires (for each plate) ...
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### A.C. through resistance

There is a topic in my physics book "A.C through resistance". And in this topic there is a sentence " the applied voltage has to overcome the drop in resistance I.e V=IR." What do ...
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### Newton's 3rd Law Coil in Magnetic Field

When a current-carrying rectangular loop is placed in a magnetic field, the forces acting on either side of the loop which is perpendicular to the field provides a torque which rotates the loop. ...
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### RMS value of Alternating values [duplicate]

What is a RMS value and what is the point of RMS value? Why do we calculate it? Please be concise and precise and kindly express it in layman terms.
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### Voltage in Direct current [closed]

Why is voltage in direct current constant? And why does the voltage in A.C changing? Do we provide the voltage in that way?
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### Can vacuum breakdown occur from a positively charged surface?

Against a sufficiently large voltage, resistance is futile. Although the vacuum is a very good insulator, electrical breakdown can occur even in a perfect vacuum in the presence of a very strong ...
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### Right Hand Rule Help: Part 1

I thought I understood the right hand rule but I guess not. Here is how I learned it in regards to finding the direction of the magnetic field vector of a current carrying wire. Point your thumb in ...
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### Why is current in a circuit constant if there is a constant electric field?

I'm a beginner in E&M, and have just started to learn about current and Ohm's law. According to this page there is a constant electric field everywhere in a DC circuit pointing against the ...
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### Circuit (Pseudo-Homeworks)

I'm studying Kirchoff's Laws and how to find $\Delta V$ between two points in a circuit (CC). I already know how to use it but I look on internet for more exercise to learn more and find this circuit ...
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### Is Kirchoff's first law based on the probability that a current splits at a junction and goes either way?

I know that Kirchoff's law comes from the fact that charge is conserved at every junction of a circuit. But is it useful (and true) to think about this in terms of probabilities? As in, the ...
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### In an intrinsic semiconductor, are there the same number of carrier electrons and holes? Or this is just exclusive for silicon?

I am working with some polymers that behave like semiconductors when they are plugged into the current. I am calculating the mobility of these polymers and I need the value of the current density (J) ...
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### Are AC circuits limited to only a serial connection?

What would happen if you set a condensator, a resistor and a solenoid all parallel to each other in an AC circuit? Would it not work or is there a way?
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### How can more voltage give more power (do more work)?

I * V = W 1A of current @ 1V is: 1W 1A of current @ 10V is: 10W I understand that 1A is 1C-per-second, which is some amount of electrons. Intuitive so far. How can I get more power if I use the same ...
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### How is Alternating Current (AC) used in Bipolar Junction Transistor (BJT) without ruining its operation?

In a BJT (Bipolar Junction Transistor), say NPN in common base configuration, we forward bias the Base-Emitter Junction and reverse bias the Base-Collector Junction when using a constant DC supply. ...
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### Electricity vs Current [closed]

BACKGROUND: Electromagnetism has been the hardest concept in physics that I do not understand at all back in my old school. Now, I just started studying robotics which requires the basic understanding ...
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### Is the direction of current wrong in this circuit? Why? [closed]

I know how to measure the equivalent resistance of this circuit, we say R2, R3 and R4 are in parallel combination and I know the reason of this too. But if we consider the direction of electricity of ...
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### Will I get shocked if I touch only the live wire while standing bare feet on the dry floor of my appartment?

In contrary to static electricity the mains electricity must return to the power plant. When I touch the live then the current flows through my body and the floor of my appartment and through soil to ...
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### In AC, do Electrons move in perfect Sync with Generator Rotation across the whole distance?

While i'm self studying electricity, one interesting topic seemed counterintuitive to me, which is: When an AC generator connects to a long XX KM length cables; each cycle, the electrons in the cables ...
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### What material is superconductor at 394 K and 2 Mega Pascals? [closed]

What material is superconductor (high current) at 394 K and 2 Mega Pascals?
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### Calculating equivalent resistance by Wheatstone bridge concept

I've been learning about the concept of Wheatstone bridge in current electricity chapter. I attempted to solve this problem by that concept: I don't know if my method is right. I tried to take the ...
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### If the current of the branches in a parallel circuit always add up to the same total, why isn't this true in this example?

Here is a picture: I did some math and got this table: Why doesn't the current add up to the total, since it's supposed to in a parallel circuit? I used Ohm's law to calculate everything. My ...
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### Understanding the zero current in a simple circuit

I've simulated the very simple circuit shown below: As you can see, it has two batteries of 1.5 V, and three identical resistors. The electric currents passing through each wire are also indicated. I'...