Questions tagged [electrical-resistance]

The tag applies to electrical resistance and resistors. DO NOT USE THIS TAG for non-electrical resistance.

193 questions
Filter by
Sorted by
Tagged with
2k views

Deriving ODE for voltage across capacitor-RC circuit [closed]

I need to derive an ODE for the voltage across the capacitor in a specific RC circuit. The circuit has 1 resistor, one input, one capacitor and a switch. So far I have $$\frac{dv}{dt} =\frac1CI(t),$$...
557 views

Resistances in a circular loop

I have no idea what formula I'm supposed to use.I just want to know the concept that would allow me to get the answer. I know basic concepts of electricity like charge, currents, etc., but as far ...
297 views

If I put a higher voltage bulb in my car headlight, what will happen? I haven't tried it yet, but I'm wondering if it would matter. The bulb has the same wattage but a different voltage.
97 views

Hydraulic analogy and pressure in pipes

In the latest days I've been quite obsessed with understanding how electricity work through the hydraulic analogy. I still have some problems regarding how "voltage drop" works, and how pressure drops ...
3k views

Why does the potential drop across a battery and resistor equal the emf of the battery?

In this diagram you can see the potential difference across the battery and resistor is the same as the pd created by the battery (the battery and resistor are representing a battery with internal ...
3k views

Resistance between two points on a conducting surface

Suppose we have a cylindrical resistor, with resistance given by $R=\rho\cdot l/(\pi r^2)$ Let $d$ be the distance between two points in the interior of the resistor and let $r\gg d\gg l$. Ie. it is ...
145 views

If we consider the electric field to act upon charges with a force, how does it stay in line with Newton's laws?

This should be a relatively simple question. Let's say we have a constant electric field $\textbf{E}$ in a conductor. The electric current density would then be $$\textbf{j}=\rho \textbf{v}$$ where ...
711 views

Where are the negligible and infinite resistances, respectively, of the ideal am- and voltmeter?

Consider the picture below. An ammeter is shown to the left, a voltmeter to the right. They consist of a d'Arsonval galvanometer, which is a coil (with a pointer attached) that can rotate in a ...
785 views

How can the transfer function of an infinite ladder network be used to solve real world problems?

In his lectures on Physics, Feynman illustrates a mathematical 'trick' in formulating the impedance of an infinite ladder, LC network. It basically counts on the assumption that adding one more 'rung' ...
3k views

Does resistivity of material change under strain

As I am reading the document on physics of strain gauge, I encounter the following paragraph that I do not understand. How could resistivity change (delta rho) under strain/elongation? I always ...
181 views

What is the physical basis for Pedersen and Hall currents in an atmosphere?

There are three components of a conductivity tensor in atmospheric electrodynamics: the parallel conductivity along the direction of the magnetic field, the Pedersen conductivity (in the direction of ...
5k views

Power dissipated on internal resistance of short-circuited voltage source

Suppose we have a voltage source with an EMF of $\mathcal{E}$ and an internal resistance $R$. If we connect to it a perfect wire with zero resistance, we get a short circuit. The value of the current ...
2k views

How does symmetry allow a rapid determination of the current between $A$ and $B$?

The following was originally given to me as a homework question at my physics 2 course: Consider the following circuit The difference of potentials between the point $V_{1}$and the point ...
158 views

Resistance of car battery

In my textbook, it is given that internal resistance of a car battery increases with decreasing temperature. But car batteries contain lead, which is a metal, and hence the resistance should decrease. ...
972 views

What is the aperture in the hydraulic analogy of Ohm's law

Note: My question is duplicate of Why doesn't water come out of tap/faucet at high pressure when I turn it on?. None of the answers given there explains how the continuity equation fits properly. That'...
35 views

Thermal dissipation and local Ohmicity of nonlinear components

In this answer, it was established that Onsager relations make a one-to-one correspondence between the linear relationship between voltage and current, and entropy creation rate in the electric ...
385 views

Is this circuit a series or parallel circuit?

I saw a definition of a parallel circuit as a circuit with more than one path for current to flow. Is that the definition that's accepted? It seems like a good definition to me, but does that mean ...
244 views

What is the voltage at every pair of points along a ideal wire that is connecting the two terminals of a battery?

If you stick a wire across a battery, obviously it is going to discharge the battery. This will be due to a voltage difference between the two terminals. However, the equation $V = IR$ tells you how ...
818 views

What does Potential Difference between a load/resistor mean?

Guys this has been bugging me for ages and all the answers i found online were unsatisfactory. My questions is, what does difference in potential or potential drop after current passes through a load/...
2k views

Can a capacitor be charged without having resistance in the circuit?

I was looking for the fact when a capacitor is directly connected to battery without resistor what will happen? If possible then tell the time for charging.
1k views

Temperature coefficient of resistivity (resistance) in function of temperature

If I'm correct, the definition of the temperature coefficient of resistivity at a certain reference temperature is the derivative of the resistivity in function of the temperature, divided by the ...
105 views

Could this open electric circuit work?

Two batteries are interfaced by a resistor. Parameters such as resistance can be set arbitrarily. Does it work?
1k views

Ohm's law and an ideal voltmeter

In an ideal voltmeter there is infinite resistance so because of which no current is flowing through it and the voltage reading is not affected. The ohm's law stated that V = I * R In an ideal ...
128 views

Questions about the formula used to determine inductive reactance and $Z_t$

I am currently on the inductors unit in my Navy schooling and I have two questions about these formulas that I learned about. As I'm aware, the ability of an inductor to concentrate a magnetic field ...
497 views

Internal resistor in a diode

When we talk about the resistance of a diode (of the P and N region), is this resistance like the one inside an Electro-Motive Force or it acts like a normal resistor (external electric field exist)? ...
2k views

Power dissipation in AC RC circuit [closed]

Can anyone help me with this question? A 20 A peak-to-peak 60 Hz current passes through a 0.01 µF capacitor which is in series with a 33 Ω resistor. What is the power dissipation? I have attempted ...
1k views

Graph of 1/Current on Y, and R on X axis. What does the intercept represent?

1/I on the Y axis, and Resistance on X. Gradient represents 1/V. Am I right in thinking that the intercept is representative of the Emf of the supply? As I believe the equation would be 1/I=R/V+C, ...
4k views

RC circuit energy [closed]

I am quite new at circuit analysis and I have a question about a RC circuit, with the resistor and the capacitor connected in series. I want to find the energy supplied by the ideal voltage source ...
145 views

Can delta-star conversions be used to resolve any circuit of resistors into series and parallel combinations of resistors?

Can delta-star conversions be used to resolve any circuit of resistors into series and parallel combinations of resistors? I mean to say that if we do not utilize any other techniques like merging ...
311 views

Effective resistance of a weird looking electric circuit [closed]

A electric circuit (in the picture) is given where all the resistance are of 1 ohm. I have to find its equivalent resistance. (9,10, 11th points are conncections) My attempt: I think electron flow ...
50 views

Resistance of a Large (relative to lead contact) Conductor

How do I calculate the effective resistance of a large piece of metal between two small electrical contacts? The thermal image (from an interesting but unrelated article called An Exception to Ohm's ...
259 views

Differential resistance vs. $R = \frac{U}{I}$

Resistance is defined as $R = \frac{U}{I}$. If Ohm's law holds, $U(I)$ is a linear function and the slope of the curve is equal to the resistance $R$. I realized only recently that if $U(I)$ is a non-...
73 views

Why do Generators generate inconsistent voltage?

I'm ultimately trying to understand the function of resistors in a circuit. The way I see it, a small increase in voltage could result in a high increase in current that would "burn out" an LED if ...
288 views

Confused on Calculating Resistance Distance Matrix

I am trying to create a computer program to compute the equivalent resistance over any points on any rectangular set of resistors (all with a resistance of 1 ohm). It seems that the resistance ...
586 views

Why is current slowed down by resistance?

Let's say I wire the negative pole of a battery to the positive pole. Obviously, the battery will short circuit as the electron pool in the negative side will become attracted to the positive side and ...
493 views

Capacitor discharging through no load?

What exactly would happen in the ideal case where a capacitor were to discharge into a wire with zero resistance? Like in here: There is still charge on one plate of the capacitor, which will try to ...
112 views

AC square wave currents across resistor (no capacitor, no inductor) and gravity air resistance analogy

Update edit: my question is really does alternating electric current through a simple resistor have a mass-based inertia that introduces lag if the frequency of oscillation is high enough? Are there ...
63 views

Why does only one of the DC circuit power equations work for me here?

I know that $$P=IV=I^2R=\frac{V^2}{R}$$ I solved for the current using the loop rule $$I=.47$$ but to solve for the Power output of the 16V battery I could only find the power by finding the ...
534 views

$V$-$I$ linear OR $V=IR$ is statement of Ohm's law?

What is the real statement of Ohm's Law: $V$-$I$ is linear OR $V=IR$? Looks like V-I is linear is ohm's law and conductors don't alway obey ohm's law and R=V/I is a general definition of R wheather ...
257 views

Bird on electric wire: theoretical distance between the two bird legs [closed]

Hey guys, please someone help me with this exercise :) For our exercise, assume that the bird’s body resistance (from leg to leg) is 50kΩ. Given is a high voltage power line with a current of 100A ...
103 views

Ohm's Law and transmission of electricity

Electricity is transmitted at high voltages. It is said that this reduces current and consequently resistance. But according to ohms law, low current must face high resistance. How is this ...
Is there some other ways to deduce resistance from current, than Ohm's Law? Also, are Kirchoff's laws usually often in conjunction with Ohm's Law, because aren't $$\sum I=0, \sum V=0$$ slightly ...