The electric-circuits tag has no wiki summary.
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Calculating current used by individual resistor?
I just recently finished a test on Physics, and when receiving my scores back I missed a question. Here's what it was if I can remember it correctly:
Three resistors (10.0, 15.0, and 6.00 ohms) ...
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1answer
30 views
Experiment to find Ammeter Resistance [closed]
I've been studying experimental electrodynamics and I needed to describe an experiment to find the resistance of an ammeter if I just have the ammeter together with one voltmeter and a protection ...
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2answers
284 views
Round bulb and Long bulb in Series Circuit
If you have a series circuit with a battery, one round bulb (with thicker filament), and one long bulb (with thinner filament), the round bulb does not light up and only the long bulb lights up.
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2answers
196 views
Why does the current stay the same in a circuit?
I was informed that in a circuit, the current will stay the same, and this is why the lightbulbs will light up (because in order for the current to stay the same, the drift speed of the electrons need ...
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2answers
187 views
Flow of electrons in a circuit
When the electrons flow in a circuit, so are those the electrons from the battery or are those the electrons of conductor like copper wire, etc..which are flowing in the circuit?
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1answer
126 views
What are the statuses of Silicene and Graphene for real world circuit production?
A lot of hype is out there about both of them (especially the latter) and I was wondering if there is more concrete information about them other than the news IBM posted on a circuit 2 years ago and ...
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2answers
184 views
Is equivalent resistance always lower if we add a resistor to a passive electronic circuit?
How to prove that equivalent resistance of any passive network is always lower if we add a resistor between arbitrary two nodes?
Note that this is not necessarily a parallel circuit, 2 nodes that we ...
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1answer
452 views
How is contact resistivity defined for a Schottky contact, or the Schottky barrier height for an ohmic contact?
Based on the transfer length method (TLM), one can accurately calculate the contact resistivity for an ohmic contact, by evaluating the absolute resistance measured through the test structure and ...
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1answer
147 views
What electric potential is found over individual resistors connected in series to an AC power supply?
Given a set of resistors connected in series to an AC power supply:
What formula governs the peak-to-peak voltage which will be measured when voltage is probed over individual resistors and sets of ...
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1answer
56 views
How we approach RLC circult from RLGC model?
In the text, it introduces a practical model to investigate a transmission line (like BNC cable), it considers the transmission line has resistive $R$, inductance $L$, conductance $G$ and capacitance ...
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2answers
549 views
Ohmic and Non-Ohmic devices
Why do some conductors follow Ohm's law and some do not? Isn't there any universal law that can explain the flow of current?
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1answer
345 views
Effective resistance of inductor
In a lab experiment, we connected a simple circuit: an AC voltage source, connected (in series) to a variable resistor and an inductor. We measured the current in the circuit, and the voltage that ...
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2answers
721 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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1answer
223 views
Circuit Simulation
I am making a circuit simulation program, and I am not sure how to simulate the behavior of Diodes.
Take this circuit:
...
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1answer
146 views
Frequency Response RLC circuit - Current against Frequency graph - Symmetry?
I understand that in a Frequency Response experiment dealing with an RLC circuit, the graph of Current against Frequency is supposed to be symmetrical about the resonant frequency theoretically.
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2answers
94 views
Electronic filter
Can you explain, please, step-by-step how Electronic filter does work?
For example, high pass filter. I know It's a trivial things, but I can't get it completely. Don't bring me formula and etc... ...
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1answer
208 views
Solving a circuit with Kirchoff/Ohms Law
Good evening,
I haven't had physics since year 7 and now I need to use elementary things in university. Since I lack a lot of basics I am now trying my best to fill these holes. Currently I am stuck ...
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3answers
209 views
Compute closed line integral of electric field in circuit
I have a circuit where resistor is parallel to capacitor, which is charged with voltage U. How to compute line integral around closed loop to get the result of Kirchhof second law - ...
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5answers
526 views
Parallel circuits - Overall resistance decreases with additional resistor
Let's say that there is a parallel circuit with two identical resistors in parallel with each other. If a third resistor, identical to the other two, is added in parallel with the first two, the ...
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2answers
397 views
An Ideal Transformer
In a transformer assumed to be transformer, power in the primary is equal to power in the secondary. So in a sense, the power in the secondary is 'fixed'. Output voltage in the secondary is also fixed ...
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3answers
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Why is current not 0 in a regular resistor - battery circuit immediately after you closed a circuit?
In regular open circuits with either a capacitor or inductor element, (when capacitor is uncharged) with a battery, when a switch is closed to complete the circuit the current is said to be 0 because ...
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2answers
104 views
Are there general circuits that differentiate/integrate empirically?
Is it possible to construct simple circuits, that given a time-varying input, produce an output that represents the derivative or integral of the input with respect to time?
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3answers
147 views
How exactly does a resistance reduce current?
I've heard that resistors are used to decrease current to a particular appliance, such as in the regulator of a fan. However, I've also heard that the total current in a circuit is always the same- in ...
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3answers
2k views
Finding current using EMF & internal resistance
What exactly is the difference between internal resistance and resistance?
This came up in the context of a homework problem I have been given:
The circuit shown in the figure contains two ...
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2answers
43 views
Different batteries connected in parallel
If we have 2 batteries one of emf x and the other is of emf y and we connect them in series we get an effective emf of x+y.
But what if we connect them in parallel, how to calculate the emf now?
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1answer
66 views
Can someone explain this intuitively please?
In a static situation we defined voltage as energy/unit charge, or j/c. As the distance between the charged particles increased, the voltage decreased. Now why do we not apply this in a simple DC ...
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1answer
74 views
Measure the voltage of a resistor without error
We have a simple circuit given, a resistor $R_x$ and a fixed current source with $I = 50 \, \mathrm{\mu A}$. Now over the resistor there is a currentmeter which has an internal resistance. In any case ...
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2answers
389 views
Why does the light bulb's brightness decrease?
The book said that the brightness of R1 would increase and R2 would decrease. I don't understand this at all.
Why does adding a wire from b to c change anything to R1?
Shouldn't charge still flow ...
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1answer
1k views
What defines the brightness of a bulb?
So I have a question. There are three identical bulbs, 2 of them are connected in parallel and the third is basically in series, on the same circuit. If the one of the lamps in parallel breaks, what ...
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1answer
2k views
Current against the inverse of resistance graph, $I = V/R +c$
If I have a plot of current ($y$ axis) against 1/Resistance ($x$ axis).
The circuit it is measured from is a simply 2 resistors connected in parallel to battery, where the potential across the ...
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3answers
81 views
Capacitor Charging and Discharging when connected to the ground
When we charge a capacitor using a battery and then remove the battery, the plates of capacitor becomes charged. One holds positive charge and the other one gets equal negative charge. o. k. ?
Now ...
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2answers
246 views
Does a current carrying wire produce electric field outside?
In the modern texts of electromagnetism in the presence of stationary currents the electric field is assumed conservative $\nabla \times E =0 $. Using this we get $E_{||}^{out}=E_{||}^{in}$ which ...
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1answer
63 views
Why does the presence of a battery change whether a circuit is in parallel or series?
If I take a closed circuit with two capacitors and a voltage difference, the circuit is apparently in parallel, but if I introduce a battery, the circuit is in series. Why does the presence of the ...
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2answers
243 views
Why and how does symmetry work in circuits?
Why symmetry work in circuits? In my book there is no mention explanation as such for symmetry arguments and circuits. But there are circuits that are very difficult to solve without symmetry. Also I ...
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2answers
133 views
Can inductance or resistance be negative or “infinite”?
Since the potential different or voltage drop is positive (am I allow to say voltage drop or potential difference in the presence of a changing current?), the current flows from right to left since ...
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1answer
211 views
Imaginary voltage in simple RC circuit
As a homework assignment, we have to find $U_a(\omega)$, that is the voltage that drops over the right resistor in relation to the frequency $\omega$ of the input AC voltage $U_e$.
For the two ...
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1answer
978 views
How to calculate the charge and the potential across a charged capacitor charging an uncharged capacitor?
Initially, there is a single capacitor $A$ attached to a power source that charges it to a certain voltage $V$. Once it is charged, it is instantaneously removed and placed in a circuit with an ...
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1answer
27 views
Finding the Steady State Charges
Here the problem states to find the steady state charges on the condensers.
But here the capacitor have a resistance in parallel connection , so how can we distribute the potential drop across ...
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2answers
103 views
Under what condition charges do not flow in closed circuit?
I wanted to ask under what conditions will charges not flow in a closed circuit. Or when is current through the circuit zero even when an EMF is applied?
Like in the case of potentiometer, we say that ...
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1answer
112 views
Electromotive force
EMF is defined as:
"The potential difference across the terminals of a battery or dry cell when it is giving no current to the circuit."
So, if current starts to flow from the ...
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1answer
76 views
What are the characteristics of a quadripole circuit element?
I'm reading Music, Physics and Engineering (H. Olson 1967), and contains models of musical instruments as electric circuits, i.e. uses the analogies between electrical circuits and mechanical ...
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1answer
137 views
Could a variable capacitor divider replace a Variac?
Hmmm... You can definitely drop down the voltage, and ideal capacitors don't dissipate any power. So it seems, at first glance, that you could use a capacitor divider as a lossless voltage step-down ...
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1answer
459 views
How are the CPU power and temperature caculated/estimated?
From Wikipedia
The power consumed by a CPU, is approximately proportional to CPU
frequency, and to the square of the CPU voltage: $$
P = C V^2 f $$ (where C is capacitance, f is ...
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1answer
102 views
Electric circuit. Slight problem with the sign on voltages
Translation first!
The figure shows an electric circuit.
a) Use Kirchhoffs 2.law on the part-circuit abed and show that $I_3$ = 0,50A.
b) Explain that $I_2 + I_5 = 2,0A$. Use Kirchhoffs 2.law on the ...
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3answers
330 views
Is this really how a capacitor works? Why doesn't it behave like a resistor?
My book says a capacitor is two conducts being connected by an insulator. Now let's take a parallel plate capacitor to simplify the problem I have.
Suppose I got two parallel plate capacitor in ...
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1answer
873 views
RC Circuit , Calculate Time Constant
Given this diagram:
With S1 switch closed and S2 switch left open, I am trying to find the time constant
Relevant equations
I know τ = RC for a basic circuit, but how would you calculate it for a ...
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1answer
43 views
When does Thevenin's theorem not apply (modelling a power source with a ohmic internal resistance)
Most physics text books say that a power source can be modelled as an EMF with a internal resistance. This is also know as Thevenin's theorem or Norton's theorem. However I have read in some sources ...
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1answer
96 views
Am I properly identifying the resistor terminal voltage?
The frequency applied to a circuit of voltage 120 V with a real coil and a resistor has a value of 50 Hz. The resistance of the resistor is 10 $\Omega$. The voltage at the resistor terminals ...
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3answers
163 views
kirchhoff's law.Simple question [closed]
So far I calculated total resistance and it is 4.66 ohms and there is 12 volt voltage across them, what is the best way or HOW to calculate current for each resistor ?
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Braess's Paradox in Electrical Circuits
According to this and other similar papers, http://www.nature.com/nature/journal/v352/n6337/abs/352699a0.html, adding a current-carrying path can increase the voltage drop across a circuit. What is ...
