Questions tagged [electrical-resistance]
The tag applies to electrical resistance and resistors. DO NOT USE THIS TAG for non-electrical resistance.
2,476
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OrCad Capture Lite [closed]
In which library can resistor be found in OrCad Capture Lite?
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Is there a strategy for reconstructing a circuit given the frequency response? [migrated]
So I recently worked with a problem where I was given a bode plot where magnitude of the transfer function (the ratio between the output and input voltage) was plotted against frequency of the system. ...
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Energy transfer in resistors
The change in electric potential energy $\Delta U$ of a charge $Q$ as it moves from $r_1$ to $r_2$ is given by
$$\Delta U=Q\Delta V,$$
where $\Delta V$ is the potential difference between the two ...
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Derving circuit equations for $RLC$ circuit such that order does not matter [closed]
Can we derive the circuit equations for an $RLC$ circuit from first principles in a way that makes it clear that the order of circuit elements doesn't matter?
Any help is greatly appreciated!
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Electrical resistance of wet wood with voltage [closed]
in recent science projects I have been studying the effect of water on electrical resistance of materials that absorb water such as wood and sponge. I am calculating resistance by reading the current ...
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Ohm and Fourier's law with Seebeck effect - derivation?
In my work, I am dealing with a mathematical model which involves thermoelectric magnetohydrodynamics (TEMHD). Ohm's law becomes modified to become
$$ \mathbf{J}=\sigma\left(\mathbf{E}+\mathbf{u}\...
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Doubts regarding Ohm's resistance from impurity scattering
It is told that electrons can scatter on impurities in crystals, which leads to resistance and Ohm's law. My problem is that even though the potential is not exactly periodic, the wave packet can move ...
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How do batteries in parallel work? [closed]
So I understand that the voltage is the amount of work done per column of charge, so its sort of a "pushing force" and amp are just the charges per second, or "amount of stuff per ...
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THÉVENIN Equivalent of Circuit [closed]
I tried to convert the right generator of, current and resistance, to a generator of voltage in series with the resistances then adding the two resistances (both in series), then simplifying, but I ...
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Find circuit resistance [closed]
It asks to find the circuit resistance, and I just can't think of any ways on how to solve this
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Electric potential across a resistor
Consider a circuit with zero resistance wires, battery, and a resistor and where the direction of the current is defined by conventional current.
Since there is an equal number of positive charges on ...
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How do I find value of $I$ using Node Voltage analysis method? [closed]
How do I find value of current $I$, using Node Voltage analysis method ?
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How to derive Thevenin Voltage formula using Kirchoff laws?
Here's a simple voltage divider. I'm learning Thevenin Circuits now and we use the formula for Thevenin Voltage a lot (very useful!) but I'm not sure how the formula arises. My professor said I can ...
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Kirchhoff's voltage law, signs?
Consider the circuit below from the book Electrical Engineering, Principles and Applications (p. 95). According to that book, we get from Kirchhoff's voltage law that
$$
-v_1+0.5v_x+v_2=0
$$
However, ...
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What effects do inductors have on circuits?
The above diagram is a simple circuit containing an inductor.
According to the right hand grip rule, it can be deduced that the magnetic field is to the right. But the magnetic field produced by the ...
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Why short circuit doesn't takes places in a homopolar motor?
In a homopolar motor we directly connect copper wire to a battery without any resistance with a magnet in bottom, so why doesn't a short circuit takes place?
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If resistance in an electric current is 0 (ideally) then would there even be current flow?
From my understanding batteries are used to charge electrons with electric potential which they then use to do work on resistors in a circuit. After doing work the electrons return to the opposite ...
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$Y-\Delta$ transformation
I'm working on electrical circuits and the $Y-\Delta$ transformation. Since I thought it was tough for me, I wanted to challenge myself with more problems, and I found this one on the web. However, I ...
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Does a Mobius resistor have zero inductance? How would you calculate the inductance?
Wikipedia describes a Möbius resistor as follows, and the Patent for this device gives a similar description.
A Möbius resistor is an electrical component made up of two conductive surfaces separated ...
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Is tap water an ohmic conductor?
Earlier today, I asked a question regarding why I was getting weird resistance readings and based on responses which I am thankful for concluded it could possibly be the electrolysis, the fact i ...
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Circuit resembling wheatstone bridge but not exactly [closed]
The below circuit resembles that of two individual wheatstone bridge arrangements as the ratio of resistances satisfy the conditions however we cannot come to this conclusion as potential at one end ...
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What happens to resistance of tap water as voltage is increased?
In recent days I have done a few experiments measuring the current of water as it goes up from 9 volts up to 36 volts, and following Ohms law to convert it to resistance. And I discovered a very ...
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What is the current going into a resistor-capacitor parallel circuit and the current coming out of it? [closed]
I'm looking at the circuit below and know that I1 = I2. Can someone explain why those 2 currents are the same?
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Apparent violation of Gauss Law
Consider the very long, current-carrying wire in the picture. On the left side in yellow, the wire has a very low resistance, that we will consider to be zero. But on the right hand side in green, the ...
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Flow of Electrons in Potential divider circuit
Take the above circuit. I'm trying to understand how current flows through this potential divider circuit. I used the following simulation to help me visualize this.
In the simulation the electrons ...
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The current in an $LR$ circuit [closed]
I am trying to understand $LR$ circuits better. I am under the impression that inductors are resistant to change in current.
So, the premise here is that the circuit was switched to side 1 for a long ...
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3 resistances in series shunted from the sides [closed]
How to find the equivalent resistance of the given circuit?
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How to derive the equation for capacitive reactance? [closed]
How to derive the equation for capacitive reactance $X_C$?
$$X_{C}=1/(2\pi fC)$$
with $f=$ frequency, and $C=$ capacitance.
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How to derive the formula for total impedance, $Z$, in an $RLC$ circuit? [closed]
Where this is an AC circuit, how can we derive the below formula for impedance, $Z$?
$R = $ resistance, $X_{L} = $ inductive reactance, and $X_{c} = $ capacitive reactance.
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Energy in $RC$ Circuit
In circuit A, the total energy dissipated in the resistor is $\frac{Q_i^2}{2C}$ which equals the initial energy, meaning that all the energy was dissipated in the resistor, and lost as heat.
Here's my ...
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Some things I can't understand about Ohm's Law [closed]
I can't understand how PD is directly proportional to resistance and current intensity at the same time, although they are inverse, I know that an increasing in PE leads to an increase in current ...
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Why does increased temperature increase resistance but decreases internal resistance?
I read that increased temperature increases the resistance because the lattice of metal ions (if we're talking about a wire) vibrates more and so more collisions occur between the electrons and the ...
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Emf induced by a solenoid
Could someone please clear my confusion regarding this concept and point out what is wrong with my argument:
Say we have a simple circuit as shown in the image:
Why is the potential difference ...
user343558
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Do a current carrying resistor experience a force?
In a current carrying resistive conductor, an electric field within the conductor creates a force on the electrons within the conductor. In broad terms, classical theory says that the electrons are ...
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Regarding Kirchoff's Loop Law
I heard that the reason Kirchoff's Loop Law (also called Voltage Law) works is because of the conservation of energy, or more precisely, as the electromagnetic field is a conservative field, the ...
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Transformers in Power transmission [duplicate]
Recently I learnt that transformers are used in the national grid to increase the voltage, so we get less current. But my understanding V=IR and by increasing the voltage we get more current, so what ...
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Superfludity and Superconductivity
Hello Im a physics enthusiast, right now im learning about superfluidity. My question is superfluidity and superconductivity are the same thing or do they work together?
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Why are Ohm's law and Ampere's law contrasting in Magnetohydrodynamics?
In the Magnetohydrodynamics the electric current is given by the Ampere's law is:
$$\nabla \times \mathbf{B}=\mu_0\mathbf{J}$$
where $\mathbf{B}$ is the magnetic field and $\mathbf{J}$ is the electric ...
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Is a superconductor 'perfect'? i.e. does current flow forever without decaying? [duplicate]
In a (say) circular superconducting loop which has a current initially induced in it, and without any further external influences, and at a temperature above 0 K and below the transition temperature, ...
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What is the historical context to specify resistivity of metals in $\mu\Omega$cm instead of $\mu\Omega$m?
The resistivity of metals usually lies in the range 1-10 $\mu \Omega$cm at room temperature as given in Chapter 1 of Ashcroft's and Mermin's Solid State Physics. Why is it not given in $\mu \Omega$m. ...
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Why does an increase in drift velocity decrease electron collision?
The original statement is "The drift velocity of electrons in a metallic wire will decrease, if the temperature of the wire is increased.". My understanding is, the temperature of a wire ...
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Physical significance of circuit eigenvalues and eigenvectors
When solving a DC circuit (say, with resistors and voltage sources only), we can use Kirchhoff's laws to get a set of equations in the currents:
$$
RI=V,
$$
where $R$ is a matrix relating to the ...
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Where can I find spreadsheet of data containing resistivity vs temperature of Type I superconductors?
Where can I find raw data containing resistivity vs temperature of all the elements classified as Type I superconductors?
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An electric motor operates on a 50 V supply and a current of 12 A. If the efficiency of the motor is 30% what is the resistance of winding of motor? [closed]
This is not a textbook question,i want to understand why it would generate two different values? and I cannot do that without invoking some form of numerical value in my question
Ok so I get that the ...
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Electric current through the resistor of an AC $(L)RC$-circuit
I have a question regarding more complex circuits.
For the sake of simplicity, suppose we have an AC source with an alternating voltage $U=U_0\cos{(\omega t)}$ and the angular frequency $\omega$ tied ...
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Calculating heat flux per unit length of wire
I'm trying to apply a formula to calculate the thermal conductivity of a certain material.
$\lambda=\frac{\dot q_1}{4\pi\cdot \frac{\Delta T}{\Delta log(t)}}$
where $\lambda$ is thermal conductivity, ...
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KVL in short circuit with 0 resistance [duplicate]
According to KVL, $\sum \epsilon = \sum RI$ in any closed loop.
However, in an ideal circuit with no resistance, R is $0$, and hence $\epsilon$ must also be $0$.
Does KVL not apply in this case?
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Derivation of the potential difference across a resistor
I am trying to understand how the voltage drop across a resistor comes about in a DC circuit. I have no concerns over the relation described by Ohm's law: the current through a resistor will be ...
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Kirchoff analysis in faraday law for RL circuit
Faraday law state that $$\epsilon_L=\oint \vec{E} \cdot d\vec{l}=-\frac{d\phi}{dt}=-L\frac{dI}{dt}.$$
So by kirchoff's analysis, isn't the equation would be like
$$\oint \vec{E}\cdot d\vec{l}=0-IR+\...
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Solving an ODE numerically with different units
I am simulating a leaky integrator with $R_m = 10^8 \, \mathrm{\Omega}$ and $C_m = 10^{-10} \, \mathrm{F}$ with an input current of $I_{in} = 10^{-9} \, \mathrm{A}$ for $0.1 \, \mathrm{s}$:
$$C_m \...
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