Drift Definition and 150 Threads

Hello PF, thanks for having me here. I am working in chemistry and we are building a atmospheric pressure drift tube ion mobility spectrometer. The drift tube consists of 20 stacked stainless steel electrodes insulated by PTFE spacers connected via a resistor chain (voltage divider) to produce...

In a forward-biased PN junction, the potential barrier decreases, allowing more majority carriers from one side to diffuse to the other side where they are minority carriers. After they cross the potential barrier, they form a diffusion current, the drift current of minority carriers is...

Homework Statement How fast would a electric arc be when it ionizes through normal, unpressured air between say, two electrodes? Not the same as lightning as it is hypothetically from an artificial source. Homework Equations How would one calculate (please include your formula's and which...

Homework Statement First off, this is NOT a homework problem. This is a conceptual question I have regarding the derivation of the drift velocity v_d =[(qE)/m] \tau Typically, when this formula is derived, you first calculate the acceleration of a particle in the electric field (qE/m) and...

Homework Statement The magnetic field of the Earth it's approximately B=3\times10^{-5}T at the equator and diminishes with the distance from the center of the Earth as 1/r^3, as a dipole. Consider a population of electrons on the equatorial plane with energy 30keV, at 5 Earth radius from the...

Following are the text from an Electrical Engineering Textbook. "it is seen that contrary to the common but mistaken view, 1. the electron drift velocity is rather very slow 2. is independent of the current flowing 3. independent of the area of the conductor" first point can be...

So in Resnick & Halliday, it explains that the drift speed, or the average speed of charge moving in a wire under the influence of an electric field E is defined by the equation ## J = (ne)v_{d} ##. Now if J,n,e are all constants then the drift speed ##v_{d}## will also be a constant. But this...

Which process occur faster in semiconductors? drift or diffusion

Hi, I need help to understand this section from my book. Here we are considering drift current Is of PN junction under open-circuit conditions. I don't understand why the drift current Is is indepentent of the value of the depletion layer voltage Vo. I think the voltage create an...

Can you help me explain this part from my book? In equilibrium, the pn junction has no external connections, i.e., the terminals are open and no voltage is applied across the device. If so, I wonder why there is drift current in the equation above. In equilibrium, the total current is zero...

I need help to understand the concept of drift velocity. Here is part from my book: Does this velocity refer to the velocity of each electron? And I don't understand the sentence: The acceleration due to the field and the collision with the crystal counteract, leading to a constant velocity...

In the derivation of drift velocity i have seen two variations and want to know which one's correct. s=ut +\frac{1}{2}at^{2} Assume that the drift velocity of any electron in any conductor is : v_{d}=l/t Due to the electric field the acceleration of electrons in any conductor...

How does conservation of energy relate to Gravity? The moon seems to rotate around the Earth for eternity (so it seems). But intuitively I would think that the energy of Gravity would eventually deplete and the moon would drift off into space. This apparently isn't the case. I know that...

Is the standard equation for drift velocity of electrons also applicable to conduction in, say, a vacuum tube? I assume it is, and if so what is the relation between the drift velocities at the interface of vacuum-metal at the anode of a vacuum diode? The current, electronic charge and Area...

Dear all, I have a question on the derivation of the drift velocity in a conductor, and was wondering if somebody could help me with it: drift velocity is the average velocity which a free charge moving in a conductor has due to the influence of an electric field applied to the conductor. In...

In probability, What is drift? I have tried to google but unfortunately I can't find the definition :( Does it mean a movement from one point to an other point, for example in symmetric random walk: let's say that ω=ω_1ω_2ω_3... is the infinite sequence of coin tosses (p the pobability of Head...

Good Morning, The equations under investigation: Electrons: J = enμE + eD(dn/dx) Holes: J = epμE - eD(dp/dx) n or p = concentration of electrons or holes respectively D = diffusion constant μ = mobility The question in mind is as follows: If holes are...

How is it possible that the two relations i.e., v=(eE/m)t and v=(eE/2m)t both holds good? where e is the elementary charge, m is the mass of the elementary particle, E is the electric field, v is the drift velocity and t is the relaxation time.

I've been sitting at my desk trying to prove this and nothing, already tried googling.. Any help guys? I want to know how to derive it from basic principles. Thanks How I came by it: I'm a high school student and was doing my exam then get asked about drift velocity and it's not even in the...

I'm having trouble understanding where the charging time in a capacitor actually comes from. Is it possible to derive the \tau of a capacitive circuit from the drift velocity of the electrons? Are charges literally moving from the conductors onto the metal plates of the capacitor?

i am really really confused . I know what Drift velocity is but the problem is I have three Sources which tell absolutely different expression for drift velocity and I cat relate . please tell which is right . This website and MIT Profs. Walter Lewin In his Lectures says Vd = eE/m x (Tau)...

Lets say we had a 10-stage linac accelerator and we were using a 200 kV supply. Apparently the K.E at stage 2 (in the second tube) is twice that of the first tube (stage 1). why is this?

Homework Statement A) A current I flows along a straight wire of cross-sectional area A. If the unit vector I denotes the direction of current flow, write down the expression for the current density J (assuming it to be uniform throughout the wire ) and give its SI units. B) (This isn't...

What is the relationship between continental drift/sea-floor spreading and global sea-level rise? Kind regards. Lucas Olsson University of Gothenburg Earth Sciences lucas@student.gu.se

Homework Statement Calculate the drift velocity of the elctrons in a conductor that has a cross-sectional area of 8x10^-6m^2 and carries a current of 8A. Take the concentration of free electrons to be 5x10^28 electrons/m^3 with 1.6x10^-19C charge on each electron. Homework Equations...

I was wondering how to calculate the drift of an object that is falling though air. If I know the mass, air density, and velocity of an object that is falling how can I calculate its movement off the center of he drop point. I.E if you looking down on a grid with x and y on the side how many x...

Homework Statement A hollow copper wire with an inner diameter of 1.4 mm and an outer diameter of 2.6 mm carries a current of 2.50 amps. Copper has an electron density of 8.5x1028 m-3 and a conductivity of 6.0x107 (ohm m)-1. a. What is the electron drift speed in the wire? b. What is the...

Hello there, I am wondering if somebody could help in an issue far from my expertise. I have some data which is reasonable to conjecture could be modeled with a random walk with drift. I am struggling though to understand how to estimate from the empriic data the most likely drift and...

Homework Statement A beam contains 4.0x10^8 doubly charged positive ions per cubic centimeter, all of which are moving north with a speed of 1.2x10^5 m/s. (a) What is the magnitude of the current density ? (b) What is its direction? (c) What additional quantity or quantities are needed...

Is there a relationship (or equation) between a charge carrier's drift velocity through a conducting material and that material's resistance? I'm trying to reconcile the idea that drift speeds are bigger when cross sections are smaller and the idea that resistance is bigger when cross sections...

Problem: An Si resistor is at 300Kelvin, and is 100μm long, 1μm thick, 5μm wide. The conductivity is 7.128 Ωcm. The resistance is 28058Ω. A voltage of 5v is applied. What is the drift velocity of the electrons, given that n = 1.01x103? Other constants: μn = 1350 cm2/Vsec μp = 450 cm2/Vsec...

Is there a physical explanation for why electrons move through a metal with a relatively low drift speed? Or is it just the observed phenomenon? I find it hard to visualise electrons moving relatively slowly through a metal despite the current flowing through it being quick...can anyone help? Thx

Homework Statement A potential diffference of V = .497 V is applied across a block of silicon with resistivity 8.75 x 10-4 Ωm. The dimensions of the block are width = a = 2.00 mm, and length L = 14.7 cm. The resistance of the block is 54.1Ω, and the density of charge carries is 1.23x1023 m-3...

Homework Statement J = ne(v). (yes. it's a vector equation and I haven't indicated that, but just ignore that. It's not important to my question.) Let's say you have some positive ions traveling downward, and some negative ions traveling upward. The electric field is downward. Let's say...

Help much needed! Thanks!So this problem has been dealt with here on the physics forums. But the fact is that answers either appear to be false and/or they differ from what other people have done. First, here's the problem: In a certain region, the atmospheric electric field strength is 120...

Calculate drift current. length of wire 1m for 10V cross sectional area = 0.001m^2 e = 1.602 x 10^-19 ue = 3.18 x 10^-7 n = 10^23 electrons / m^3 what does ue stand for? how do i calculate drift verlocity? 3. The Attempt at a Solution i am using the formula I = nAVq where...

I am using LG Optimus 2x smartphone(Gyroscope and Accelerometer sensor) for positioning. I want to get correct rotation angles from gyroscope that can be used later on for body to Earth coordinate transformation. My question is that 1- How I can measure and remove the drift in gyro sensor. The...

consider two wires of different diameter. when current enters from that of greater diameter to lesser diameter drift velocity increases. which force causes it to increase?

Seeing the other thread about "How I view AC" and the talk of drift velocity reminded me of a question I had a number of years back, and never found an answer to ... what is the electron drift velocity of an electric arc? I'd be interested in the wide scope of everything from lightning strikes...

Homework Statement "The current in a 1.70mm x 1.70mm square aluminum wire is 1.70 A. What are (a) the current density [in MA/m^2] and (b) the electron drift speed [in micrometers/second]?" Homework Equations J = I/A The Attempt at a Solution I plugged in the values for current...

Homework Statement A copper wire of diameter 2.00mm carries a current of 0.50A.The number of conducting electrons per metre cube of copper is 8.00 x 10^28. a)Calculate the drift velocity of the conducting electrons. b)What is the number of conducting electrons in 10.0cm length of the wire...

Hello, This is a problem that is buzzing me around for quite sometime since I took fundamental physics course. Consider an electric circuit with one battery and one resistor. And ignore the internal resistance of the battery and the resistance of the wires. 1) Does battery supply...

hello everyone,:wink: is this definition correct? drift current is flow due to applied voltage across P-N junction & Diffusion is flow due to different concentration of hole & electron across P-N junction. warning: [i read this definition somewhere, hence not my own work] 1:-- the...

can anyone please explain me following errors of gyroscopes used in inertial navigation systems of aircraft : a) what is transport wander , how actually it happens ? b) what is apparent drift in gyroscope ? c) what is coriolis effect and how it causes errors in gyroscopes ?

Homework Statement A physics student playing with an air hockey table (a frictionless surface) finds that if she gives the puck a velocity of 5.70 m/s along the length (2.28 m) of the table at one end, by the time it has reached the other end the puck has drifted 5.78 cm to the right but...

why are good conductors of heat good conductors of electricity as well?

Homework Statement The current in a 1.5 mm X 1.5 mm square aluminum wire is 1.10 A. What are (a) the current density and (b) the electron drift speed? Homework Equations current density: J = I/A drift speed Vd = J/ne The Attempt at a Solution It's asking for an answer in MA/m^2...

I have a small question that can't solve. How long does it take an average electron to drift 1um in pure silicon in an electric field of 10^4 V/m ? drift velocity v_d = I / (n*q*A) but don't know how to calculate can you help me ? thank you.

I'm having trouble fully conceptualizing drift current- what I always hear is that it is caused by minority carriers within one diffusion length of the junction being swept across by the electric field that is generated by the imbalance caused by diffusion of electrons. Here is what I am...

The drift speed of the electrons in a copper wire running from a battery to a light bulb and back is approximately 0.020 mm/s. The battery is at the front of the classroom and wire runs out of a perimeter of the room to the light bulb. The total length of wire is 40meters. How long would it take...