# Tagged Questions

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

2answers
4k views

### How can be the neutral wire at 0 volts when current flowing through it?

Voltage is potential difference, and current flows because of voltage. So if the voltage is zero, how can current flow through the neutral wire.
2answers
1k views

### Rate of flow of electrons in a simple circuit, given the current? [closed]

I have this question: The correct answer is C. I understand that the flow of electrons should be from Y to X because electrons flow opposite to "conventional current", which is from positive to ...
1answer
51 views

### How will open-circuit voltage affect the Fermi Level Difference

The circumstances of my question consists of this: I have two materials, copper and cesium, and they are sandwiched together with a layer of cesium in the middle. It is connected only on a single side ...
1answer
759 views

### How does a bulb light up when it's connected in a circuit with an uncharged capacitor and a cell?

Since there is a capacitor, isn't it an incomplete circuit? How does the current flow across the dielectric medium? If a bulb was connected to a cell alone and if there was a break in the wires of the ...
0answers
13 views

### Current pass through different branch of network [duplicate]

How current knows that resistance in any branch of network is law show that more proportion of it pass through that branch?
4answers
76 views

### Many cells in parallel

If two or more cells of unequal voltages are connected in parallel (with the same terminal on the same side), is there a formula that gives the net potential difference? Also, by Kirchoff's loop law, ...
1answer
63 views

### Potential difference in a circuit of n cells = 0? How?

I was supposed to find the potential difference across any one cell in an arrangement consisting of n cells of EMF E connected in series in a closed circuit and internal resistance r. I proceeded by ...
2answers
82 views

### Why is this circuit component on without a potential difference?

From the following graph, determine whether (h) will be on or off: I think (h) should be off because there is no potential difference across it. Is this correct? Edit: Using the method provided ...
1answer
113 views

### Transfer function of an RC circuit

I'm trying to reach the transfer function of an RC circuit which I am told is $$\frac {V_R} {V_\text{in}} = \frac{R}{\sqrt{(R^2 + \frac {1}{\omega^2 C^2})}} \cos(\omega t - \theta) \, .$$ Is this ...
3answers
214 views

### What's the max speed a man-made satellite can travel in space before its circuitry stopped working?

Assume it could withstand extreme temperatures in either direction. I'm mainly curious what would happen to its circuits as it approached the speed of light.
1answer
84 views

### About the combination of two signals with capacitors

Here is a link of an article I've been reading. http://www.analoguehaven.com/moog/thereminblack/hotrod.pdf In page 4 there is a circuit schematic. Notice there is a part called variable pitch ...
2answers
323 views

### How long does it take for a capacitor to be fully charged if voltage is decreased? [closed]

Above is the picture of the circuit pertaining to this question. The question asked for the time it will take for the capacitor to get fully charged when the switch is in position B? So i guess the ...
1answer
171 views

### What is the strength of the magnetic field required to penetrate an average human body?

Introduction Suppose you are an experimental nanobot researcher trial-ling a new form of medication that involves activation and control of nanobots within the cells of the interior of the human body ...
2answers
243 views

### Current on both sides of a capacitor

When a capacitor is connected to a DC circuit, what ensures that the current on both sides of the capacitor is the same? When charges arrive at one end of the capacitor they stop moving; presumably ...
2answers
61 views

### A circuit that is net charged

What differences would you measure if a circuit were significantly charged negatively? Would the resistance change? To be clear, I mean that excess electrons are added to the system. The circuit can ...
2answers
44 views

### Resistors and dependent voltage sources

why not $i(2\;kΩ)=15\;mA$ and $i(5\;kΩ)=4\;mA$?
1answer
53 views

### Will the current flow from the battery?

I am just trying to find out if the current enters into the positive terminal of the battery (if there is a battery with bigger emf ) will it get charged and charge will be stored and current will ...
4answers
330 views

### How does an inductor store magnetic energy?

I am trying to figure out what the potential energy of an inductor with a current really means. In a capacitor, the energy stored works like this: if you let the plates attract each other, before ...
2answers
65 views

### Doubt on resistor circuit [closed]

How are we able to flip the triangular resistor to the opposite breaking its connection with the lower 2r resistor?
2answers
70 views

### Why is voltage essential in circuits?

I understand what voltage is, but why is it necessary for an electric circuit to function? Why can't current flow without a voltage?
0answers
32 views

### What is the capacity of this circuit? [duplicate]

I simply can't figure out what the capacity of this circuit is. I can do the math myself, I just need a hint how to create an equivalent circuit where it is obvious what is parallel and what is in ...
1answer
155 views

### Electric Motors: why do they draw more current when stalled, and less when moving? [duplicate]

I'm familiar with how an electric motor works, and also familiar with what stall current and free current refers to in an electric motor. I'm also somehow familiar with the notions of energy being ...
2answers
928 views

### Why do high voltage transmission line workers need a Faraday cage suit?

In this video the high voltage transmission line workers are wearing a Faraday cage suit. Why is this needed? Without the Faraday cage, the resistance of the human would be very high compared to the ...
1answer
117 views

### Highly inductive circuits question in general

I've been reading about self-inductance in circuits in M. Purcell's Electricity and Magnetism and came across an interesting fact: "What happens if we open the switch after the current $I0$ has been ...
1answer
63 views

### Are LC circuits preferred as series or parallel? Why? [closed]

Are LC circuits preferred as series or parallel? I recently studied about LC circuits in parallel and asked my tutor about whether the inductor and capacitor could be connected in series. He said it ...
1answer
50 views

### Does the power of the resistor change when the battery is changed?

Wanted to know whether the changing of a battery (potential difference)affects the change of power consumption of a resistor of a bulb. please tell me how the change will occur?
1answer
74 views

### Calculating resistance [duplicate]

I am really confused please help me! I want to find the resistance between a and b! But i am not able to understand which resistances are in series or which are in parallel! What i think- e and a ...
2answers
215 views

### potential difference across a bulb

I am doing some self studying over the summer for fun and I'm working from a book that does not provide answers. I came across the following question, and I will present my solution. I was hoping ...
0answers
78 views

### LC-circuit with AC-supply - Current flowing through the coil

A parallel LC-circuit is connected to an AC-supply as in the figure below. $I_{tot}(t)=I_0sin(\omega t+\phi)$, $\phi$ is the phase angle between $V_{tot}(t)$ and $I_{tot}(t)$ a) ...
1answer
379 views

### Circuit with capacitor and two resistors - total current - charge - differential equation [closed]

Consider the circuit below consisting out of a capacitor C and two identical resistors R. For $t<0$ the switch is open and the capacitor is uncharged. At $t=0$ switch is shut and the circuit is ...
5answers
3k views

### What causes contact resistance?

When two components are combined in an electric circuit, there is apart from their own resistances a contact resistance at their junction. This causes a sudden voltage drop of $V_{drop}=R_{contact}I$....
3answers
345 views

### Why do inductors maintain the exact same current?

As we know, a capacitor will maintain the same voltage across its poles even if it is disconnected from a battery source. For example, in this problem: http://www.unm.edu/~toolson/rc_circuit.gif ...
0answers
81 views

### Maximum current in LC Circuits

Two capacitors of capacitance $C$ and $3C$ are charged to potential difference $V_o$ and $2V_o$ respectively and connected to an inductor, all three in series. Now the switch S is closed. Find the ...
1answer
392 views

### Loss in energy while charging a capacitor

Suppose a capacitor having capacitance $C$ is being charged using a cell of emf $E$. By the time the capacitor is fully charged, the cell has supplied $QV$ energy while the potential energy of the ...
2answers
331 views

### Calculating the resistance of a 3D shape between two points

If I have an arbitrarily shaped object made of a uniform material of some specified resistivity, how would I go about calculating the resistance between two measurement points with known contact ...
0answers
52 views

### What is the form of the skin effect in exponentially decreasing (or exponentially increasing) voltages?

I tried to replicate the standard derivation of the skin effect for exponentially shrinking or growing voltages (idealize the surface of the wire as a half-infinite volume of conductor) but I'm not ...
2answers
4k views

### Why does voltage change in series circuit but not in parallel circuit?

Voltage divides after every resistor in series but not when placed in parallel. Please explain this with using very less or no mathematical equations. I have tried searching for an answer online but ...
1answer
36 views

### How is this trigonometric substitution achieved for this simple capacitor circuit equation?

In a simple circuit with one capacitor and one AC source, where the equation of the source voltage is v(t) = Acos(ωt), I was trying to follow how they found the ...
1answer
138 views

### How uniquely determined is the impedance of an infinite-chain circuit?

A recent question asked how to find the impedance of an infinite chain of series-plus-parallel circuits. The standard trick is to split the chain after the first link, and treat the tail of the ...
1answer
136 views

### Impedance of the infinitely long circuit

Is there a way to find impedance of the infinite circuit like this? It will be much simpler if one has either parallel or series combination but here is both.
1answer
171 views

### Does the skin effect, eddy current / hysteresis losses contribute to Johnson noise in an inductor?

Based on my very basic understanding of the Johnson noise, it's not just a DC phenomena, but should change with frequency in a system, where there is a frequency dependent, real component to the ...
1answer
56 views

### Current - Voltage curve for non-ohmic material

Forgive me for I am a math student and am quite ignorant in these topics. I would like to know, at least implicitly, how the current intensity of a lightbulb, for example, relates to the potential ...
1answer
95 views

### DIY Ring Light: Grounding Bulbs in Circuit

I'm looking at making a DIY ring light using multiple fluorescent light bulbs. I'm in New Zealand and we get 230-240V and an current of 10A. I know from this I could rig up to 24 100W bulbs in series ...
1answer
22 views

### How does static protection really work?

I've read that while working with circuits you want your body to stay at the same voltage as the components you are trying to protect. So you're supposed to connect those wrist things to one of the ...
2answers
111 views

### Please give your valuable opinion in this capacitor problem! [closed]

The plates of a parallel capacitor are given charges +4Q and -2QThe capacitor is then connected across an uncharged capacitor of same capacitance C. What is the final potential difference between ...
2answers
168 views

### Why the electric potential energy the charges carry in a electric circuit does not vary with its distance to the opposite terminal?

I understand that with wires assumed to be ideal, there is no resistance and subsequently no force acting on electrons, hence no work done and p.d. across any segment of wire. However, as the ...
2answers
67 views

### According to calculations why the current of a battery of a mobile is high?

If you pay attention to the features of your mobile's battery the voltage would be around 3-4V and power is 4-5 Wh (14400-18000 Ws) and with calculating the current you can find a very high number(P=V*...
0answers
113 views

### Ampere's law and magnetic circuit

For magnetic circuit there is an equation NI=HL. This equation is obtained by applying Ampere's law. H is magnetic field intensity and L is the length of the circuit. In following picture the equation ...
1answer
40 views

### Electricity parallel combination

Why is resistance lower in a parallel configuration and therefore current is more? Shouldn't resistance be addition of all resistor's resistance?
3answers
137 views

### Electricity series connection of resistor

In simple circuit is current in wire different from current in resistor as wire also opposes the flow of electrons so wire should also be added in series connection of resistor