Inductor Definition and 450 Threads

Homework Statement The current in a 28mH inductor is known to be −10A for t≤0and (−10cos(400t)−5sin(400t))e^(−200t) A for t≥0. Assume the passive sign convention. At what instant of time is the voltage across the inductor maximum? What is the maximum voltage? Homework Equations v(t) =...

Homework Statement The L=100 mH inductor in the following figure has an initial current of Io=10 mA. If the voltage is, v(t)=1e−10t+2e−5t V, what is the current, i(t), through the inductor? Express your answer as a function of time with units of mA. The figure shows an independent voltage...

If we have a resistor and inductor in parallel, how does the resistor maintain a potential difference equal to our emf? Am I correct in saying that for the inductor to maintain a voltage difference, there has to be some change in current, so that the current going through the resistor is also...

Making resonance using "simulated inductor" (op amp) I want to have a circuit that responds strongly (gives me a good measurable voltage) to a 10kHz sound input. To do this, I thought about hooking up a microphone and making a resonance circuit (using inductor and capacitor) to amplify the...

Homework Statement Assuming steady-state sinusoidal ac.A voltage of 240V at 50Hz applied to an inductor yields a current of 4A.Assume negligible resistance.Find inductance, max stored energy. Homework Equations E=0.5Li^2 X=2*pi*f*L The Attempt at a Solution V/I=X Which I...

Hi all, I'm working on designing a variable inductor using a ferrite core. The basic idea is that I have a large wound inductor on the central arm which I pass a DC-current through, and a smaller, variable inductor on one of the side arms. As you increase the current through the main winding...

Homework Statement Not really relevant here. Homework Equations U = LI^2 -- maybe? The Attempt at a Solution http://i.imgur.com/Pq4dOex.png The picture is there, as well as the answer. Why is that the answer? How do inductors work when completely disconnected, and not in a...

Homework Statement Hey everyone, I got a question wrong on my homework that I'm trying to figure out. I'm given this: "a 500uH solenoid(inductor) with an air core is 10cm long has an inside diameter of 1cm. How many turns of wire does it have? Homework Equations L = N2*u*A / l...

Homework Statement A long, fine wire is wound into a coil with inductance 5 mH. The coil is connected across the terminals of a battery, and the current is measured a few seconds after the connection is made. The wire is unwound and wound again into a different coil with L = 10 mH. This...

resister // inductor -- calculate resulting impedance Hello, how 600Ω || 300jΩ = 120 + j240 ?? how do you get the value 120 + j240 from 600 register parallel wih 300jΩ inductor?

Homework Statement We have this circuit: (uin+)---[1/jωC]--[jωL]--[RL]----o------uout+ (resistor of value R connecting the two lines at their o's here) (uin+)-------------------------o------uout- Find an expression for the quotient of u(in)/u(out), and then find the resonance...

I have some confusion about how emf across an inductor is generated: The potential difference across an inductor is an induced emf produced by the changing magnetic flux through the coils of the inductor. In general, electric potential is a scalar potential of the electric field. Hence the...

Hi guys, So I'm starting to learn about magnetic fields and electrics fields, one of the equations we use is v= -L*di/dt ... I've been trying to figure out how it's derived, in my book it says: it starts off like this: 1. v=-dθ/dt (faraday's law) <- why is there no N(no. of turns)...

Can someone help me solve this? I don't really understand how to do this. A 1kvA reactor's capacity is needed to be enlargedto 81kvA. How much does its dimension needs to be multiplied? Hint: when its dimension is m times enlargened, surface A'=m'A, flux ∅'=m^2∅, current I'=m^2I, voltage...

CAN Current pass Through INDUCTOR? how the AC circuit is completed when Inductor is in it as no AC pass through it?

At resonance (## \omega_0^2= 1/LC##) in an LCR-Circuit the phase angle given by \theta=\tan^{-1}\left( \frac{\omega L - 1/\omega C}{R} \right) obviously is zero. And still there are other phases to deal with. This I don't understand. Let me elaborate. For example when calculating the amount...

"when we apply AC to an inductor (pure inductance), the current will lag the applied voltage by 90 degrees. " how this happens? why current lags applied voltage by 90 degrees? :confused:

Homework Statement Homework Equations k=1 inductor(left)=400j inductor(right)=1600j The Attempt at a Solution how to do this! help me. my caluclator can't solve 3 rectangular form mesh currents equations so i cannot solve for individual currents for all 3 loops! i just guessed...

Hi, I have just seen this statement in another forum: An inductor is a constant current source for a limited time until its energy is expended. A capacitor is the counterpart being constant voltage until its energy is spent. I am not quite understand it. Can you help me? This is not a...

Hi everyone, Say I have a series DC circuit. The circuit contains a 100V DC source, a switch, a 1.5H inductor, and a 1nF capacitor (all in series). If I close the switch for 2uS what is the current at that time? Initially I thought I could rearrange V=L*di/dt to V*Ton/L = di/dt which would...

This is really not a homework, just need help to understand some concepts. In a circuit includes R, L, C in series, we apply Faraday's law: I*R + Q/C + 0 = - dψ/dt Here VL = ∫E*dl across the inductor is zero. I know this because the inductor has no resistance and according to Omh's law VL =...

Hi, Homework Statement This is not a formal HW question, yet I was wondering whether one of you might be willing to answer it nevertheless. According to Fraday's law, ε = -∂\phi/∂t. If I reversed the direction of the current in an inductor used to measure ε, would that have any effect on...

Hello everyone, I am working on a coil design and have a question. The coil is meant to operate in continuous conduction mode, so the current waveform is a ramp waveform. B=V*t / N*Ae When calculating V*t do I use 1/2 t (since the current only increases for the first half of the...

Hello, I'm wondering, if you have an inductor and resistor that has the switch open, so current is zero. Then you turn on the switch, the inductor is going to resist this change, it wants to be zero, right? Therefore, why doesn't the current indefinitely stay as zero, since the inductor would...

Homework Statement Consider the circuit which consists of two ideal inductors L_{S} ,L_{P}. These inductors are magnetically coupled with mutual inductance, M. It is possible to replace these magnetically coupled coils by three coils which do not share magnetic flux linkages. The two...

Homework Statement The switch in the circuit has been closed for a long time before it is opened at t = 0. Find: a. IL(t) for t > 0 b. i0(t) for t > 0 c. V0(t) for t > 0 Homework Equations equivalent resistance, equivalent current, equivalent voltage voltage...

Homework Statement at t=0 switch S is closed. Just after the switch is closed what are i1, i2, the potential difference across V2 across resistor 2, and Vl across the inductor? A long time after the switch is closed, what are i1, i2, V2, and Vl? Emf = 12V, R1= 15 ohms, R2 = 25 ohms, and L...

Homework Statement From the circuit find the impedances of the capacitor and inductor Is(t)=15 cos(500t) A Homework Equations The Attempt at a Solution So is this right? Convert the 15 cos 500t into polar form, 15<0 I. Then the resistor is 8 ohms, so 15*8 = 120 V...

Homework Statement The tuning circuit in an FM radio receiver is a series RLC circuit with a 0.200 µH inductor a. The receiver is tuned to a station at 104.3 MHz. What is the value of the capacitor int he tuning circuit? b. FM radio stations are assigned frequencies every 0.2 MHz, but two...

I have a circuit-diagram for a train which in the final stages converts the power to a 3-phase AC voltage (IGBT) that is the excitation for the motors in the train. However, right before the converter module there is a power inductor. I have looked through some literature and on the internet but...

While studying electrical science, I was told that when an alternating current passes through an inductor, current lags voltage by 90•. And when through a capacitor, current leads voltage by 90•. But while studying transistors in electronics, I was told that AC passes through a capacitor but...

Question about continuous conduction mode converter I have a few quesitons about CCM converters I have posted a basic schematic of the circuit in question as an attachment. The circuit is a series LC circuit in which the inductor and capacitor charge during the on time. During the off time...

Hi, Two questions I'm finding it hard to get my head around with inductors... Say we have an increasing current, this is going to cause an increase in flux in one direction, which will induce an emf to drive a current which produces a magnetic field to oppose the change in flux. Than doing...

I have a buck regulator running hot. I reduced the switching frequency and the temperature is almost normal. The current rating of the inductor is high(2A) compared to current consumption on the board (300mA). Why does reducing the switching frequency solve the heat problem? Does the...

i have to make a 10mH inductor coil for an LCR resonant circuit.could someone please guide me on which gauge of wire to use and how to wind it to make a coil within 5% variation? i need the coil to be close enough to 10 mH for resonance. looking forward to ur help...

Homework Statement http://imageshack.us/a/img832/1651/homeworkprobsg32.jpg At t= 0, the switch is opened. Calculate the current i(t) for t>0 Homework Equations V(t) = L* dI/dt V = IR I = V/R voltage division, current division, KCL, KVL The Attempt at a...

How can you get from the first expression to the second. I've done calculus, just need a fresher. I don't know how to deal with the dt/dt thanks

I was trying to study the inductor role in Flyback converters and all, they seem to rely on the principle that the inductor is first energized while the switch is closed and then, it acts as a voltage source itself when the switch is opened. All that is good, but I am confused with the...

Homework Statement A step input of 100V is applied to a resistor of 50Ω in series with an inductor of 10H at time t=0. Calculate the time at which the voltage across the resistor equals the voltage across the inductor Homework Equations Im not sure which equation to use, i know τ=L/R...

The other day one of our power labs we were using rather large inductors; that is, approximately 10"x4" in the shape of a doughnut. There were 4 connections into the inductor. We connected a wire from one to the other, and then used the other two connections as any other inductor. Does that...

I did an exercise today on my breadboard with an inductor that I made from a coil of 22 gauge stranded hookup wire wrapped in a helix coil around a 60d nail I found in my garage. The power source was a 9V battery. I took a measurement of just the battery fully open with my digital volt meter and...

Homework Statement A coil has self inductance L of 2 Henrys, and a resistance R of 100 Ohms. A DC supply voltage E of 100 volts is applied to the coil. Show graphically the approximate rate at which the current increases at the moment of switching on (t=0) and after 10ms. Confirm your...

Hello! I am having an issue with getting any graphs on inductance or induced voltage. In the attached circuit: What I have is a 28Vac source w/ 400hz and 2 coils (R=18.6ohm each) that are connected with a common. In the model: I have a core in the center that will be able to move up...

I know that the there is some small capacitance between the windings of an axial inductor let's say, but how does one measure this? The inductor is a short on an LCR meter...

Homework Statement a resistor, a capacitor and an inductor are connected in parallel to a source of oscillating EMF of frequency 955hz and amplitude of 1.0x10^3 V. the resistance of the resistor is 200Ω. what is the maximal instantaneous current in the resistor? if we want to make a maximum...

The standard explanation is that the magnetic field stores the energy but when I start considering different sizes of a single loop inductor with a current flowing in it things start to get a bit vague. As the loop diameter is increased the inductance goes up so the single loop can store more...

Homework Statement I am asked to find the equivalent resistance of a simulated inductor shown above. We are told not to worry about the simulated inductor circuit. The simulated inductor will be incorporated into a larger circuit as shown below. 2. The attempt at a solution I am really...

The current in an inductor when energy is stored. Please help! Homework Statement What's the current in a 15mH inductor when the stored energy is 42μJ Homework Equations E = 1/2 L i^2 The Attempt at a Solution .000042J = (.5)(.015H)(i^2) .000042J = (.0075)(i^2) .0056 =...

En and Ec are the non-conservative and conservative electric field respectively. I've quoted this from the textbook I'm using (University Physics by Young and Freedman 12th edition). Now, it seems to me that the author just invoked the assumption that the inductor have negligible resistance...

Homework Statement An inductor is subjected to the current in the graph: L = 100mH = 0.1H I) Calculate and graph the voltage over the ideal inductor. II) Repeat for non ideal inductor with a resistance of: RL = 50 Ω Homework Equations U_{L}=L*\frac{di}{dt} U_{av}=L*\frac{Δi}{Δt} The...