# Tagged Questions

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

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### Why does adding more components in parallel increase the current?

Why does adding more components in parallel increase the current? Shouldn't the charges be more distributed, so they can't 'push' each other at the same rate anymore?
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### Ambiguity on the notion of potential in electrical circuits?

As everybody else I have been taught elementary electrical circuits from secondary school to engineering level in analog electronics at university. Invariably, the notion of potential used to ...
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### Potential Dividers - Why do I need the second resistor?

So I am doing the OCR Physics GCSE course, and I have just learnt about potential dividers in electronic circuits. I get that the first resistor steps down the voltage so a component with a lower ...
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### solution of the equivalent resitance [duplicate]

I searched and I found answer to my question.Although there are many solution, I did not understand logical mean properly. my question is that in the below circuit, How can I find equivalent ...
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I think it is not dublicate question. Although there are many solution, I did not understand logical mean properly. my question is that in the below circuit, How can I find equivalent resistance? ...
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### explanation of the solution of equivalent resistance [duplicate]

I think it is not duplicate I wonder that explanation of the solution I searched and I found answer to my question.Although there are many solution, I did not understand logical mean properly. my ...
78 views

### Potential Difference Across Components in Parallel & Series Circuits

So I have two questions, but they're kind of linked so I'm putting them in one. 1) I have a simple circuit with a battery connected to three lamps in series. If I then add a second battery but ...
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### What actually goes on in RLC circuit?

I already have difficulty understanding how each of the RLC circuit elements work individually as it is, and I have no idea how they work simultaneously in an RLC circuit. My schoolbook represents the ...
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### In which direction should flow of electric current be taken while solving problems?

Consider a simple circuit with a battery of $\theta\ \text V$s, and two resistors of $R_1 \ \Omega$s and $R_2\ \Omega$s connected in series. Let us assume that $R_1$ is connected nearer to the ...
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### Voltage in a circuit across a metal wire

I have a cell of e.m.f. 2.0V and negligible internal resistance, which is connected to a variable resistor R and a metal wire. The resistance of the metal wire is 3.4 Ohms. The resistance of the ...
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### Ion Source Design

I want to design a DC arc discharge ion source but I can't find a good book that explains how to do it. Can anyone please recommend me a book or paper that explains this? thanks
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### Explaining why there is current in a circuit with a capacitor whilst the capacitor is charging

The question I'm trying to answer is part b) of the question below: My answer was: As some of the electrons will initially be repelled by the electric field of the negative plate, there will be ...
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### Why is there electric field OUTSIDE a battery?

Correct me if I'm wrong, but a battery's electric field is like an electric field of a capacitor consisting of two parallel plates. But we know that the electric field outside the two plates is zero. ...
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### Thevenin's Theorem problem

I don't understand why $(c)$ is same with a circuit when removing power source at $(b)$. Isn't this same with this one? But how could this circuit could be $(c)$? . .
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### Capacitors in an AC circuit

Can I combine capacitors in the same way for an AC circuit as I can for a DC circuit (In series or in parallel)? Does the same apply for simplifying resistors?
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### 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 ...
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### In the Nernst equation $E=E_{cell}-\left(\frac{0.0592V}{n}\right)\log Q$, what does the $E_{cell}$ represent?

In the Nernst equation $$E=E_{Cell}-\left(\frac{0.0592V}{n}\right)\log Q$$ what does the $E_{cell}$ represent? I read that $E_{cell}$ is the standard state condition of the cell, let us say that we ...
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### Can current be induced in a grounded conductor?

I'm engaged in a rather lively debate with a group whose physics I believe to be a bit shaky. Basically they're claiming that if a conductive object is grounded to earth, the current cannot be ...
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### How does a capacitor pass the flow?

Capacitor has just two conductor surfaces which have no touch. How can it pass the electric flow when there's no touch between the surfaces?
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### Analogy in combination of batteries in series and pn junction diode circuit to find potential difference

Can I use the analogy of combination of two batteries to get the potential difference between two points(by applying Kirchhoff's law) in case ,if a pn junction diode is used in the place of other ...
6k views

### Voltage and Current in transformers

In transformers, the ratio of the voltages equals the ratio of the turns - so double the output coil's turns and the output voltage doubles. Then, in order to conserve energy, current halves. This ...
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### How does the introduction of a new ground affect a circuit?

I was talking today at lunch with a friend about getting shocked by a light socket while changing a light bulb the other day. The glass got separated from the metal threads where the positive and ...
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### Inductor circuit

Consider a inductor circuit with an inductor connected to a DC battery and a switch. Initially the switch is open. At time $t=0$ the switch is closed. What will happen to the inductor just after the ...
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### Deriving the charge as a function of time in a discharging capacitor

There is obviously something I have not understood well. In Kirchoff's second law, we take the potential difference of batteries and capacitors with the sign that we traverse it. So, let's assume that ...
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### DC motor, bulbs

What happens when you are getting low voltages ? Why fan becomes slow and bulb become dim ? Dye to low voltage or current? If power is V*I then due to low voltage current becomes low or not Many ...
23 views

### Impedance of transformers

What does mean by impedance reflecting? Why this phenomena occur? What does mean by Zl=zs to gain max power but power is constant in transformers?
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### Equivalence between voltage drop across capacitors and resistors?

In simulating a circuit, comprised of 2 capacitors of same size but different dielectrics, their capacitance ratio ${C1}/{C2} = \epsilon2/\epsilon1$. Problem is, in finite element programs, I am ...
642 views

### How to imagine the first few moments of an LR circuit?

For example, there's a very simple circuit which only contains on resistor. So according to Ohm's law, we have: $\mathrm{emf} = IR$ As we know when time $t = 0$, the current must be $I = 0$. However, ...
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### AC Electricity as a Simple Harmonic Oscillator

Can the net motion of electrons in an AC circuit be considered an example of simple harmonic oscillation. Furthermore, how can the general formulae of SHM be adapted to suit a scenario of an AC ...
22 views

### Triphasor Problem

Given the data presented in the following link I have to get $R$ for $P = 90~\textrm{kW}$ and the line currents $i_1$, $i_2$ and $i_3$. Any ideas?
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### Validity of Kirchhoff's current law

Is Kirchhoff's current law valid for rapidly varying currents such as a one with a frequency in the order of 10KHz?
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### If a purely inductive circuit is started in presence of gravity, will the power source ever run out? [closed]

I have read that purely inductive circuits do no work. So if an Inductor with an AC source, coming from an inverter is set up, will the source of power ever run out due to work against gravity? This ...
4k views

### How does series circuit differ from parallel circuit?

Why does same current $I$ flow in the series circuit but it isn't the case with resistors in parallels?
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### What is reactive power?

I am trying to understand what is reactive power. I have read that it has a relation with voltage, that is has a relation with the creation of a magnetic field in a motor, that it is coming and going ...
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### Voltage and reactive power

Why are reactive power and voltage related? When the control system of a generator increases/decreases the current of the rotor, voltage and reactive power are increased/decreased.What is the relation ...
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### How does current split in a parallel circuit? [closed]

I'm having trouble understanding why the current that goes through the 6 ohm resistor is 1A when the proportion of the parallel resistors is 2:1 from top to bottom. Could anyone explain how current ...
51 views

### Equivalent DC circuit with charged conductors

I am trying to find equivalent circuit for a circuit composed of interconnected capacitors when isolated pieces of conductor may carry nonzero electric charge, and I have been struggling with this ...
46 views

### power in an ac circuit - difference between in series and parallel

In AC-circuits, we have different kinds of power: active power $P$, reactive power $Q$ and apparent power $|S|$. Let's say we have a circuit with a resistor $R$ and an inductor $L$. My understanding ...
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### How to find when an LRC circuit is critically damped mathematically, given a set of voltage/time data?

In an undergraduate-level experiment to approximate the resistance at which an LRC circuit system is critically damped, I found the resistance range within which the system is likely to be critically ...
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### How Calculate the electric field into capacitor [closed]

Hello i have a problem with this exercise with capacitor, I have to calculate the electric field between the capacitor plates (neglecting the edge effects ), but I do not know how to do Text: A plate ...
21 views

### Does electron drift model apply to current in liquids

The electrons in a metallic conductor, tend to drift at abysmally slow speeds, but still a current is able to flow through it, because the net movement is in the direction of the applied emf. How is ...
167 views

### Resistance vs Power experiment - not linear relationship? [closed]

Ok, so I have been performing a lab experiment in class involving resistors. We were asked to set up 3x 47Ω resistors in 6 different combinations in a circuit with a 6V power supply. We also attached ...
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### Is there any intuitive or mathematical explanation to this case regarding Kirchoff's second law?

I was trying to prove Kirchoff's Voltage law, which says that in a series circuit, $\Delta V_{battery} = \Delta V_1 + \Delta V_2 ... + \Delta V_n$, where n is a number of resistors. Before proving ...
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### Current in parallel circuit and short circuits

I would like to ask a question which is partially addressed in this question: Current in Parallel Circuits Since the voltage in parallel is constant, why is it that when there is a short circuit, no ...
37 views

### Continuing on voltage drop across a resistor [closed]

What exact wire diameter allows approximately $6.25\cdot 10^{18}$ electrons to pass in 1 second? Will a thinner diameter or a wider diameter wire allow the same approximate number of electrons in a ...
87 views

### $P=VI$ and $P=V^2/R$ [duplicate]

How come equation a) $P=VI$ says if you double voltage, power is doubled while according to equation b) $P=V^2/R$ says power quadruples? Which one is correct?
543 views

### Ammeter range and shunt resistance

Its said that for an ammeter to give good reading, the full current in the circuit must pass through it. But if I am right, the ammeter is basically a galvanometer connected parallel to a very low ...
87 views

### Voltage Drop and Current Flow

Assume we have a source @100 DC volts in series with a 200 ohm resistor. According to Ohm's Law, current flow in 0.5 amps. Voltage drop across this resistor is 100 volts and equal to the source ...
418 views

### Derivation of capacitive reactance

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 t}dt\\=Q(0)+\frac{I_oe^{j\...
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### How does a capacitor get charged while the charger circuit isn't closed? [closed]

a capacitor is a very known device in circuits that can be used as a short-time battery by charging it using another source, but how does it really get charged? if the plates of the capacitor don't ...