Questions tagged [electric-circuits]

An electronic system, with closed loop current flow, and relative electrical potentials present across electrical components.

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34 views

What does the labelling of a conductor such as: 24 W 12 V mean? Does this mean the resistance of the wire or the current?

So I came across a question where a lamp was labelled 24 W and 12 V. 2 lamps that were identical and had this labelling were then put in series with a voltage supply of 12 V. Obviously the individual ...
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Equivalent resistance of a circuit with backwards diode [closed]

Please help find equivalent resistance of this circuit, as well as the current drawn by it.
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Hamiltonian of a quantum circuit including a diode?

The LC circuit has a Hamiltonian: $$\hat{H}={E_L\over2} \hat{\varphi}^2 + 4E_C \hat{n}^2$$ where $\hat{\varphi}$ is the magnetic flux and $\hat{n}$ is the number of charge. What is the Hamiltonian ...
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$B$ and $H$ fields in magnetism

I read a lot of answers that propogated the idea that $H$ field is independent of material considerations. If H is really independent, then why do books consider H in the core of the magnetic circuit ...
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$B$ and $H$ fields at boundary of two media

i was reading about magnetic circuits with air gaps and found that H in the gap (Hg) and H in the core of the magnetic material (Hc) were different, but the B field was equal throught (since flux will ...
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Determining emf of a cell using a potentiometer

When we are to determine the emf of a cell, we find the null point and balance length using the cell whose emf is to be found out. But there is some internal resistance of the cell. Why isn't any ...
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A misunderstanding concerning self induction of an inductor

If there is an inductor in a certain electrical circuit, from Faraday's Law we know that $$ \oint \vec{E} \cdot \vec{dl} = -\frac{d\phi_{magnetic}}{dt}$$ I see everywhere that when doing this line ...
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Can anybody explain how to simplify the following system of capacitors given in the image below [closed]

Can anybody explain how to simplify the following system of capacitors given in the image below.
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Why don't electrons still have energy after completing a circuit with a battery?

Firstly a battery causes an accumulation of electrons in the negative terminal right? Hence the positive terminal is relatively positive and so an electric field is produced. This electric field will ...
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Why are the capacitors in this circuit in parallel but not in series?

In the circuit, the capacitors are said to be connected in parallel. Why is that so? Edit: The switch will be closed and C2 is fully charged by C1 and no more current will flow between C1 and C2. The ...
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A zero potential difference in a wire in a parallel circuit, but there is a problem?

I was studying parallel and series connections for circuit and came a cross a problem that could not understand. Now look at this problem: lets say current (I) is coming from the left: the current (I)...
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Why does a real DC circuit with 1 resistor have uniform current?

Imagine a DC circuit with small but non-zero resistance in wires and large resistance in a single resistor in series with the battery, all ohmic. Connecting the battery I imagine a surge of electrons ...
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Ohm's Law gives me different values compared to the practical experiment with a multimeter - can you explain why?

I am studying physics in high school and am trying to understand electronics. Using Ohms law I calculated VIRP values for a simple circuit with three 1000 ohm resistors and a 9V battery. I then set up ...
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Can Faraday Law be applied to a loop with some twists and turns in it?

Consider the above question. I have been able to solve the question understanding area vector of A and B are opposite in direction. However I have some conceptual doubts. In Faraday Law, when we say ...
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Intuition behind Johnson-Nyquist noise?

I've been doing a lot of reading on Johnson-Nyquist (thermal) noise lately, and sadly much of the material I've come across either looks at things from a very engineering prospective (that is, little ...
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Are voltages in series LCR circuit added vectorially?

I am trying to understand Kirchhoff's voltage law in reference to AC circuits and this is a dummy problem I have solved to show my doubt.Quoting my textbook, voltages across components in a LCR ...
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1answer
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How did shorting the source make the voltage in the resistance 0? [closed]

Hello! I'm quite confused about this circuit. I've come across somewhat a solution "the current takes the path of least resistance" but I'm not so sure what it means and implies exactly. I ...
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Bandwidth of a RLC Circuit

Bandwidth of an RLC circuit is defined as the angular frequency difference for which Power dissipated through circuit is half of that dissipated at resonance. What is so special about this range that ...
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How to solve circuit in static electricty? [duplicate]

I just found this question, but I don't know how to solve it. The question has a answer, but still it don't give me the formula. the answer for numeber 1 is 0,0 a for number 2 is 40 for number 3 is ...
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Wire specs current is given at 1100v. what is the amp load for 200v? [closed]

Also, what is "in conduit trunking" vs "unenclosed"? where for example 1.5sq mm copper is rated at 16a and 19a respectively. is it simply R=V/I for this purpose?
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What is the formal definition of series and parallel connections?

It seems half the time I'm just guessing whether it's series or parallel, is there not a way to definitively determine whether a given connection is series or parallel just by looking at it?
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Voltage Across a Resistor RLC

Given an RLC circuit I want to model the in- and out-of-phase of the voltage across the resistor $R$ as a function of the frequency $\omega$ of the AC-supplied voltage $U = U_0 \cos(\omega)$. The ...
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Which has more sensitivity: a 10 volt per unit length or 30 volt per unit length potentiometer?

according to me sensitivity of potentiometer should be like: with less increase in length , i am getting more volt that is 20 volt/l should be more sensitive than 10 volt/l because < i am getting ...
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Return current in a pcb stripline

In a pcb stripline with ground reference planes above and below the signal trace, I understand that the return current will split between both planes and return to the supply. What would happen if one ...
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1answer
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Will an appliance metal case get alive if touched by the neutral wire?

My phyiscs textbook only discusses what will happen if a live wire touches a metal case and how it turns alive, however, I was wondering, will the same effect happen to the metal case if touched by ...
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Is resistance or voltage more effective in reduction of power loss?

It is commonly stated that increasing voltage of the source reduces power loss. If voltage of source is increased current through the circuit increases, resulting in more power loss (than with less ...
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Experiment to show that current leads voltage by 90° in capacitor

I understand that current leads voltage by 90° in capacitor. How does one show that it is true by an experiment?
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Why in potentiometer we says that potential gets decreased?

here potential is said to decrease from a to b ,why it is so and why there is potential drop from a to b please explain?
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Is it right that in LCR cicuit Power loss $=VI$ not equal to Power loss $= V²/R$?

I had a doubt today (this is not my homework question, I made it up). Suppose in a LCR circuit at resonance we take out power loss as $P=VI \cos\phi$ (power factor and $\cos\phi$ becomes 1) and in ...
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Why changing the distance between two parallel plates capacitor will affect its charge?

I have a question that is bothering me, Lets assume that I have a parallel plates capacitor with distance $d$ between them. Now connect it to DC voltage source $V$. according to equation $$V=\frac{Q}{...
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Is the current in a resistor different from that in a circuit? [duplicate]

My understanding is that since Current = Charges/Time. If there exists a resistance to the flow of charges, then that must mean the charges slow down, meaning that more time is required to pass ...
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Is the current obtained using Ohm's law that which passes through the resistor or that which passes through the circuit?

Shouldn't the current passing through a resistor be lesser than that which passes through a circuit? My understanding is that since Current = Charges/Time. If there exists a resistance to the flow of ...
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What happens when one connect 110V appliance to 220V supply? Is there any way to safely connect such appliance to a 220V supply without damage? [closed]

What happens when one connect a 110V appliance to a 220V supply, and vice versa? Please explain in detail. Is there any way to safely connect such an appliance to a 220V supply without causing any ...
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Transformers: How does current in primary coil change?

I was doing a question on transformers and found this really confusing question: A 100% efficient transformer converts a 240V input voltage to a 12V output voltage. The output power of the transformer ...
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Can the $Q$ factor of a system exceed unity ($Q>1$) while the maximum gain is 1?

when calculating the quality factor of an acoustic system using FWHM definition I get 39. the maximum gain is approximately (see the attached figure ). when I calculate $Q$ in time domain using the ...
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Amplifiers without vacuum tubes or transistors? [migrated]

Are there amplifiers that can work without vacuum tubes or transistors? Is it possible to create a working amp with high power without vacuum tubes or transistors?
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Energy Conservation: How is Heat generated in a loop with Time Varying Magnetic Field through it?

Consider a circular loop kept in a time-changing magnetic field. We know, via Faraday Law, that EMF is induced across the loop and hence a current appears in the loop. Let there be some Resistance ...
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Why is the worst case input/output impedance of an $RC$ filter $R$?

I'm going through the Art of Electronics in my spare time, and I ran across a problem I've been scratching my head about for a few days. The book states that in the worst case for any $RC$ filter, the ...
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What exactly is Electric Potential Difference of a cell?

What I thought Electric Potential Difference of a Battery was : • It was the factor that caused electrons in a circuit to move from negative terminal to positive terminal. •It is a variable factor w.r....
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Intuition in an LR circuit — Why does rate of increase in current decreases with time?

Consider the below LR circuit. The current law for the circuit is: $$i=\frac VR(1-e^{- \frac {Rt}L})$$ And Voltage across inductor is: $$L\frac {di}{dt}=V(e^{-\frac {Rt}{L}})$$ This means that the ...
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Realization of SSH model through electrical circuits - how to measure impedance?

I am trying to reproduce the results given in this paper. The authors create a circuit whose $I-V$ equations are similar to the Hamiltonian of the SSH model. And then through impedance measurement, ...
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How do I precisely calculate the Current during a short-circuit event?

I am curious about this problem due to an observation last week. A standing fan I had has its wires exposed, then it short-circuited since the neutral wire was touching the live wire directly. Then I ...
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Wouldnt the electric potential energy be constantly decreasing in a circuit and not just at points of resistance?

Good day, I am a beginner in electrical engineering.I was wondering when the positive charge is passing through the circuit isn’t it constantly losing electrical potential energy as it is flowing from ...
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What will happen if we try to take a voltage reading by keeping it in current mode in a multimeter?

There are different modes present in a multimeter. one is the current mode and voltage mode for their respective measurements. what will happen if one try to take a voltage reading by keeping it in ...
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Heat produced by resistor in a circuit with charged capacitor and no battery [closed]

C2 has a charge of 8C and 4F capacitance. C3 has no charge and 2F capacitance. S2 is then closed for a long time. What is the total Joule heat generated in resistor R2? The answer is 8J/3 but I'm not ...
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Is an infinite amount of heat is produced in an L-R circuit? [closed]

Consider a simple L-R circuit. When I tried to find heat generated in an L-R circuit, I got the result as, mathematically speaking, the work done by the battery, and the heat produced in the resistor ...
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1answer
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Why doesnt a capacitor discharge when you ground one end?

I have grounded one end of my capacitor after charging it but the voltage drops at a steady pace not as if it has lost charge. Is this because the opposing charges on the opposite plate are keeping ...
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Kirchhoff's voltage law for an ideal circuit containing only a capacitor

Let's say I have an ideal open circuit (i.e. there's no resistance in the conductors) containing only a charged capacitor and then I close it. Now, the charge on one end of the capacitor will move to ...
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Work-Energy Theorem in Resistance circuit with variable Voltage

Consider a simple resistance circuit with constant Voltage. At any stage current is constant and the drift velocity of electrons is same.The change in Kinetic Energy is zero and the work done by ...

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