Current flow Definition and 138 Threads

I have big trouble understanding how current flows in semiconductors. As i have understood it it has to do with "valence" and "conduction" bands. I see valence bands as an discrete energy level within an atom that are possessed by electrons. These electrons do not contribute to a net current...

Homework Statement There is a diagram in a book that shows a water pump sending water down a hill that then rotates a water wheel. The water reaches the bottom reservoir and is then carried back up the hill by the pump to start the cycle again. Q1. Use this model to describe an ammeter...

Take some high voltage power line. Place a conductor between the wire and Earth ground. Current goes to ground. Why? I understand what is voltage, resistor, circuit etc. I do know that the wire is at a higher voltage than the ground. But isn't Earth also a kind of huge resistor? Thus preventing...

Homework Statement We have seen that a coulomb is an enormous amount of charge; it is virtually impossible to place a charge of 1 C on an object. Yet, a current of 10 A, is quite reasonable. Explain this apparent discrepancy. Homework Equations I = nqvA The Attempt at a Solution i think it...

This is something I have been trying to figure out lately, but I can't seem to wrap my head around it. So, according to a definition in my Physics textbook, while the electrical potential difference established between two terminals encourages the movement of charge, it is resistance that...

When current flows in a conductor, is it evenly spread out in the conductor? Not flowing(concentrated) in a certain part? And if we split the conductor into smaller pieces(visually not physically) the current divides out evenly so that when all those split pieces add up it equals the same as the...

I need to know approximately what percentage of a vehicle with an airtight passenger compartment must be filled with water before it sinks to the bottom. The fact that it is airtight may normally prevent it from sinking, but if a window was cracked from impact, and water slowly trickled in...

This thread will concern the workings of potentiometers, but I could use some help tackling something first. I will explain in my next post! Assume I have shorted out a battery with some resistor. I always thought that if you had a high enough resistor value, you could stop current from...

Homework Statement What is the current flow when a diode is connected in series with a resistor and battery.The cathode of the diode indicated as A is connected to the positive battery terminal.The Anode of the diode indicated as B is connected to the one leg of the resistor and the other is...

I am trying to determine the size of a conductive 2-D sheet that has a specified degree of increased resistance (or reduced conductivity) compared to an infinite sheet. Imagine that electrons enter the infinite sheet and exit the sheet at 2 points which are 1 unit of distance apart and aligned...

Hi, I'm taking a basic electricity course right now and I'm having trouble understanding a formula. The way they have their example makes no sense to me. Can anybody verify that their example is correct and explain a little bit for me? See attached file.

I know how to calculate current flow across a resister from the voltage, but what about current flow into a battery? Do I need to put a resister in the system so that I know how much current is flowing, or does that drop the voltage to the battery too much? I'm guessing the battery has an...

In the following diagrams: and: Is current flowing horizontal or vertical&horizontal? I'm sure for the rectangle one the flow of current is horizontal, but not sure of that square.

I have a simple series circuit, with a 9V power supply, and a 1 ohm resistor. If I place to identical fuses in series on opposite sides of the resistor that are rated for <9A, which fuse will blow first? I am essentially asking if current flows identically through all points in a wire the...

I am a physics student with very limited experience in electronics and I have been tasked with making an receive coil for use in an MRI machine. The design of an RF coil amounts to constructing to what essentially amounts to an LC resonator with a set resonance frequency. The design of my coil...

Homework Statement when the balance point is achieved , there're no current passing thru , so Galvanometer should show 0 . Am i right... so there's no current passing thru the 20 ohm resistor . so my working is ( 8.1/120 )(40) = 2.7 V ... correct me if I'm wrong...Homework EquationsThe Attempt...

Homework Statement i) A particular source of potential difference is capable of providing a maximum potential difference of 2 Volts. Sketch how you would connect two such sources to provide a potential difference of 4 Volts. ii) If each source can provide a current of 20 mA before its...

Homework Statement [/B] A 1.5 volt battery is short-circuited by a 2–meter long wire having a resistance of 0.02 ohm per meter. How large is the current flowing through the wire (before the wire or the battery burn out)? Homework Equations Voltage = Ampere x Resistance Ampere =...

I have a small conductive, non-magnetic particle in which I will induce a fairly strong electromagnetic field into using a flow of current. I will then disconnect the power source that makes the particle electromagnetic. How long will it take the magnetic effect of the particle to diminish...

Homework Statement A current-carrying ohmic metal wire has a cross-sectional area that gradually becomes smaller from one end of the wire to the other. How does the current vary along the length of the wire? Homework Equations a. It increases. b. It remains constant. c. It...

1. Homework Statement [/b] In the figure, two parallel wires carry a current I in opposite directions. A rectangular loop is midway between the wires. The current I is decreasing. The induced current through the resistor R is: A: Zero B: from b to a C: from a to b Homework Equations...

Hi, I didn't know if this is a homework question it didn't fit any of the template layout. If it is let me know and I'll post it there but I have some question that have become very frustrating and more frustrating in finding answers to them. If you are able to answer this question you just...

Homework Statement (a) Calculate the magnitude and indicate the direction of flow of current in Figure 20.40. E2 = 19.0 V and r2 = 0.55 Ω. (b) Find the terminal voltage of each battery. Homework Equations V = Ir The Attempt at a Solution I found the answer for part a...

Homework Statement I don't quite understand how diode problems can be solved. Whereas having inverse direction of current flow (on paper) when working with resistors didn't matter, working with diodes does. In real life if current flows through diode from - to + on paper it doesn't. I...

If iam using a magnetic material as a shaft. The rotating shaft in a magnetic field can cause the flow of current? resulting current flow in shaft?? please clarify me...

In a single circuit I've always understood that a neutral was a return essentially completing the circuit for the current to flow but I know that losing a neutral can cause imbalanced load and burn up equipment, my question is, how is this possible? If I were to open the hot, it would simply...

Hello, I'm working on obtaining an equation that will help me model the behavior of velocity as a response to the current flowing to a coil in a MagLev. I have tried to relate momentum and electromagnetic momentum: m*v=F*Δt F=q(E+ v X B) V= (q(E+ v X B) Δt)/m Am I going the right...

Hi ,imagine a situation , we have a large tesla coil, a faraday cage , a man in it and he cage is grounded. Now we switch on the coil high frequency high voltage currents makes a breakdown of air and produces a path so that the current goes and strikes the cage.Now according to faradays law the...

AC Electric Neutral Current "Flow" Hi everyone Can someone point me in the right direction here please. Happy to do the digging, but so far I can't find anything that helps! In an AC alternating-current electrical circuit, the Neutral wire is ultimately connected to "mother earth" / "big...

Here is an image show how currents flow in NPN transistor from Microelectronic Circuits by Sedra Smith: Can you explain more about injected holes (iB1)? I can't imagine how holes can flow into emitter (N type) Is it possible to for holes to flow from base to emitter?

If potential difference between two points of wire is very low(as potential drop is very low due to low resistance) then how can there be flow of current in the wire?

Just to be be clear about what I am asking, I would like to ask a few different questions 1st: Are these assumptions correct: 1) In DC, current flows through a circuit due to the movement or flow of electrons. So in a DC circuit anyone electron will do a complete lap ( or circuit ) of the...

Let us consider a circuit... There's a 10 V battery... A Rh(resistor with changeable resistance) and another battery is connected in parallel in the circuit... Now current I (due to the 10 V battery) divides into two parts when it reaches the parallel connection... Let's note them by Ir and...

The direction of Earth's magnetic field in the northern hemisphere is downward and to the north. If an east-west wire moves from north to south, in which direction does the current flow? I have no idea how to approach this problem. It was on my physics test and I got it wrong and I'm doing...

In a simple circuit where i have a bulb connected to a wire that's connected back to the bulb, how will the electrons flow? I'm thinking it would look like this http://postimg.org/image/6jd2dg2md/full/ where as one electron comes out of the negative end, another electron goes in the positive...

Hi I have a basic question. When birds sit on an overhead line, they are sitting on a bare conductor which is transmitting high power, but they don't get electrocuted. I think the answer is because the bird itself doesn't complete the circuit so current won't flow through them, but I don't fully...

I have some doubts regarding Current Flow and Capacitances... I Read this somewhere.. " an electrochemical cell supplies energy to move a charge from its low energy, low potential terminal to the high energy, high potential terminal. In this sense, the cell supplies the energy to establish...

Is there any current flow through the diode in this circuit (attached) ? My initial answer was that there was none but then again I just wanted to confirm because all the other questions don't have any current flowing through them either. Looked fishy/

Look at the picture... Here current is flowing through a semiconductor... First think about holes... The holes will pile up on the upside... But if you think about electrons then the electrons also pile up on the upside... What's wrong here? Is it wrong because it is more appropriate to...

You know current will flow only when the path is complete and closed. During lightning, that doesn't happen. Lightning dies after some time? Its not a complete or closed path. How can you tell that charges are flowing or current is flowing?

So i was doing a question from Irodov(Q 3.238) & got stuck for hours (as expected) The question goes - A thin conducting strip of width h is tightly wound in the shape of a very long coil with cross-section radius R to make a single layer straight solenoid. A direct current I flows through...

Hello; Im new, just registered and I am very sorry if this problem is posted somewhere already or not. So, I am interested to learn about what is ment when we talk about electrical current, specifically positive and negative charges. Ok, so we have two charge carriers, positive and negative...

Hi all, I'm having a small question about current flow direction indication in circuit diagrams. Its shown as current flow from +ve pole to -ve pole, but -ve pole has higher electron concentration (potential) & electrons flow from -ve to +ve. Whats the logic of showing the direction of...

QUESTION: I have two solenoids, one connected to a power supply so that current flows through the coil, and the other connected to a galvanometer. When I disconnect the power supply in the left coil, current flows momentarily in the right coil. Explain why and predict which way the...

Hello Can anybody help me determine where does current flow in the circuit on the picture below: How it goes when Uul is >0, and how when Uul is negative (<0). There is inverting OP AMP, and Uop will be >0 when Uul is <0, right? And how it goes then through diodes? Zener diodes here...

Gday All First time post here. I am trying to construct an animation of electron and hole flow through a conductor. I understand that the theory now is that electrons are not really like the old solar system model ,but more like energy cloud layers around an atom ,how would you go about...

Homework Statement I attached a picture of the problem. I am confused about how the current source will affect the direction of current flow. Does the current flow in the direction of the current source arrow? If not what does the arrow dictate? Our professor said the direction of the...

If I have a fuse with a rating if 5A and when I connect 10 bulbs in parallel, the current flowing will be 5A. When this happens will the fuse melt? Or does the current have to be more than 5A for it to melt?

How the current Flows from gases ?

I'm trying to make a small crystal radio and have managed to wire up the antenna and the head phone jack but I haven't got any diodes suitable for the voltages I'm using. I have some LEDs but will these dissipate too much current or cause any harmonics or interference with the signal?