Tagged Questions

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

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If a heater was turned on its' own wire, would heating of the wire cause the resistance to increase, thus the current into the heater to decrease?

I'm thinking not, because; A) It wouldn't make much sense in the real world because you'd need to avoid ever turning a heater towards its own wire, and you'd have to regulate the temperatures of any ...
817 views

Significance of Time constants in LR and RC circuits [closed]

What is the significance of a time constant in a circuit? Is there any use of knowing the time at which the charge in a capacitor is 1-1/e times its total charge? What is special about the capacitor ...
51 views

Thevenin theorem

Hi i got the trouble and i miss the concept about v out in thevenin i have the circuit like this so i used voltage divider for finding the voltage at point 1, but how to finding voltage at Vo , ...
86 views

Current through moving bar on rails with non-constant magnetic field

I am working on the problem pictured below and I cannot figure it out. I have been using the equation d[flux]/dt = -BLv and V = -d[flux]/dt. However, since the magnetic field is not constant through ...
40 views

How soon would electrons start flowing once I closed a switch on a circuit that was one light minute away from the battery

In a circuit, how do electrons "know" when the circuit is closed? To my understanding, they do not start flowing unless the circuit is closed. How soon would they start flowing once I closed a ...
150 views

What happens in circuits where the propagation time of the electric field is significant?

Kirchhoff's current law assumes "that whenever current flows into one end of a conductor it immediately flows out the other end". I want to understand what happens when we cannot make this ...
6 views

What is resultant capacitance of this unbalanced bridge? [duplicate]

What is net capacitance across the point A and B
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How big of a capacitor would I need to release 5 amps for 0.2 seconds? [closed]

Just what the title says, 5 amps for 0.2 seconds. Please bear in mind that I have absolutely no grasp on electrical wiring, so I would appreciate simple terms. What I need to do is release a burst of ...
404 views

Capacitors in a series circuit with dielectric

When a dielectric slab is inserted between the plates of one of the two identical capacitors in Fig. 25-23, do the following properties of that capacitor increase, decrease, or remain the same: (a) ...
60 views

How do i interpret the following electric potential diagrams?

We recently started to learn about electricity in school and I'm trying to understand the concept of voltage(potential differance). From what i understand, electrons flow from the negative terminal to ...
58 views

What is voltage in a circuit?

What is voltage in a circuit? We just started learning about electricity in my school. From what I understand; potential is potential energy per Coulomb and voltage means difference in potential. So, ...
51 views

Deriving Loop Equations in a Circuit with 2 batteries?

First time posting here, so please help with formatting. I need help deriving loop equations for this becaue the 2 batteries/power supplies are throwing me off. https://i.imgur.com/MJH6mIM.jpg The ...
76 views

Given a large, multiloop circuit with resistors and batteries and I'm not sure how to simplify it. (When NOT to combine resistors?) [closed]

So here's the circuit, and the question is looking for current i: All resistors are 2 ohms and the batteries are 5 volts. I'm trying to apply the resistance combination Kurchov rules to make this ...
42 views

Heat creation of computer electronics

The first thing I learnt in physics was that whenever anything happens heat is created. Irrespective of the process. With that in mind, electronics clearly create heat (ohmic heating I think?). But ...
21 views

energy conservation in an electric circuit

Define a reactive (lossless) and reciprocal two-port by its impedance matrix $[Z]$, so that $[Z]+[\bar Z] = [0]$ and let the source impedance and open circuit source voltage be $Z_s$ and $V_s$ at ...
27 views

Electrostatics effect on resistance values [closed]

Consider two parallel metallic plates separated by a silicon dioxide layer of thickness tox (like a capacitor). In this case I am applying a positive voltage to the top metallic plate. Now due to ...
66 views

Physical intuition behind the fact that current in an inductor lags behind the emf/voltage by $\frac{\pi}{2}$ in an AC circuit

What exactly is the reason that current through an inductor in an AC circuit acquires maximum value after quarter a time period ($\frac{T}{4}$) of the emf getting the max value?
129 views

Inductive reactance 0 for dc current?

Inductive reactance: $$X_L=\omega L=2\pi f L$$ is the opposition to the flow of current by an inductor. Frequency $f$ being $0$ for a DC current, the inductive reactance too is $0$. But doesn't the ...
44 views

When electrons move against the opposition of resistance, "friction" is generated. Just like mechanical friction, the friction produced by electrons flowing against a resistance manifests itself in ...
117 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 ...
80 views

Finding the resistance of platinum wire [closed]

Im currently lost on solving this potentially simple electricty question and was wondering if anyone in this community could hint me or tell me which equations and why these equations would be ...
52 views

Is there a way to draw a thermodynamic diagram analogous to an electrical schematic for simple ideal systems?

I have a small system in air (which should be part of the schematic), consisting of several cylinders within one another and contacting ideally at various spots. How do I model it as if it were an ...
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How can I redraw this circuit where I can apply Kirchoff's Voltage and Current Law to get correct Voltage at V?

I thought I can draw the -5V as a source but it did not turn out to be right, unfortunately.
283 views

Why does all the current flow through a short circuit if its voltage drop is considered zero?

Path of least resistance vs. short circuit I know the path of least reisistance has been clarified already However, to derive the equations you need to assume that the voltage of each parallel ...
37 views

magnetising the material using coil

I studied that when alternating current is passed through the coil ,the coil produce magnetic field (primary) as shown in figure,when any conducting material placed near to that field, eddy current ...
334 views

Let $Q(t)$ be the charge stored in a capacitor $C$ in $t$ time for alternating current. Now, $$\displaystyle Q(t)=Q(0)+\int_{0}^{t}I(t)dt\\=Q(0)+\int_{0}^{t}I_oe^{j\omega ... 1answer 55 views Voltage Circuit I feel that I don't understand how voltage works in a circuit. I understand voltage to be electric potential energy per unit charge (kq/r). In the case of a circuit, electrons flow from low potential ... 1answer 90 views Must a universal motor always rotate at the frequency of the AC current? So here I have a picture of a motor (I think it is a universal motor but I am not sure). My question is if this motor is connected to an A.C. supply, does it have to rotate at the frequency of the ... 2answers 35 views Filament lamp (V,i) behavior between 0 and 1V I was wondering why the behavior is more "chaotic" at 0~1V when compared to 2V+ (which is when it starts to glow). 2answers 2k views Why do voltmeters and ammeters have high and low resistance respectively? I understand why voltmeters are connected in parallel and ammeters are connected in series, but why is it that to measure voltage, you must have high resistance, and to measure current, you must have ... 2answers 66 views Parallel resistances How is the net resistance lesser than the least resistance when resistances are connected in parallel? The electrons will have to flow through one of the resistances, right? To me, it seems like the ... 3answers 2k views Potential Difference in a wire with no current Recently I encountered a circuit problem. Imagine, you have an ordinary circuit with a resistor and a battery(60\,\mathrm{V} emf and negligible internal resistance denoted by r) with a switch(S_1) ... 2answers 103 views Why is an LC oscillator lossless, but C V^2 / 2 energy is lost to a capacitor connected to an ideal voltage source? It is mathematically proven that in an LC oscillation that all the energy gets transferred from the inductor to the capacitor and vice versa. There is no energy loss as there is no load in the ... 0answers 24 views Is there a difference between a ground pin and voltage by an ungrounded plug and just a grouned plug? I have a cortex dj mixer with an ungrounded plug but with a ground pin (that I don't use for now). But I get a lot of noise if a connect my speakers to this mixer, so maybe I need to ground this ... 0answers 48 views Energy conservation applied to a generator If a turbine runs with a kinetic energy of some joules, the electricity produced must also have the same power given out, according to the energy conservation law. Now if the electric flux is ... 1answer 50 views What holds good? [closed] If the 1 ohm resistor is replaced by a 0.2 ohm resistor. what will be the current flowing through ? What actually determines it ? the OHM'S LAW or POWER CONSERVATION ? 5answers 4k views Difference between live and neutral wires In domestic electrical circuits, there are 3 wires - live, earth and neutral. What is the difference between the live and neutral wires? As there is AC supply, it means that there are no fixed ... 2answers 1k views What's the difference between a positive and a negative current? Say I have a wire, and I connect a current source on its left end, and a ground to its right end. Then using my power supply I source a positive current, does this mean that electrons will move from ... 0answers 60 views Why does this electrometer works? I was looking at this electrometer (measure of static field E). The principle is : E moves electrons between the 2 electrodes into the coil and there is a magnetometer inside the coil. This ... 1answer 101 views How to solve difficult resistance puzzles? [closed] How does one solve really difficult resistance puzzles? These are presented in the form of a diagram with multiple resistances in various combinations. I have done some puzzles by reducing the puzzle ... 1answer 37 views Why a capacitor's potential increase until it is equal to the potential of the battery? I understand that the potential between the plates of the capacitor increases as the circuit runs, but why it stops increasing exactly when it becomes equal to the potential of the battery? 1answer 22 views Current and Heat in Circuit [closed] Find current through the circuit. Also, find heat generated in each resistor. MY ANSWER:- In Parallel, 1/Rp = 1/12 + 1/6 = (1+2)/12 = 4/12 Rp=3 ohm Total Resistance = 4 + 4 ohms = 8 ohms ... 2answers 121 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 ... 3answers 134 views Why is the total potential difference in a circuit the sum of the individual potential differences? I am having difficulty in applying my understanding of electrical potential to circuits. Why is the total potential difference in a circuit the sum of the individual potential differences among ... 2answers 383 views Current in Inductor and Capacitor with DC voltage source? [closed] A DC source in series with pure Inductor and pure Capacitor no Resistance. How the current will flow in this circuit? What I just know is that in the beginning Inductor will behave as an open circuit ... 6answers 185 views Current when resistance is 0 A short circuit has \rm 0 resistance. We use Ohm's Law \rm V=IR. If \rm R=0, then \rm V=0. Doesn't this mean \rm I can theoretically be anything? Thus \rm I can be like \rm35A for ... 1answer 36 views Detect Breaks in Mesh Circuits [closed] PS: I will mess up a lot of terminology throughout the question. Anyways, I want to build a circuit which is in the shape of a mesh, something like a table and subsequently detect whenever there is ... 0answers 125 views Loaded Quality Factor I came up with an expression for the reflected power of a resonator:$$\left| \Gamma \right|^2 = 1 - \frac{1-\left(\frac{\kappa - 1}{\kappa + 1}\right)^2}{1 + 4 \left( \frac{Q_U}{(\kappa + 1)} ...
The following circuit is connected in series and $240V$ power supply. Bulb $A$ has $240V$, $100W$ rating. Bulb $B$ has $240V$, $500W$ rating. Calculate the power dissipated at bulb $A$ and $B$ ...
Let us say that we are interested in finding the voltage (potential difference) $y$ across the resistor. The circuit consists of a battery, a resistor and an inductor. The problem can be solved by ...