What is Ac: Definition and 1000 Discussions

A 20.0-mH inductor is connected to a standard electrical outlet (ΔVrms= 120 V; f = 60.0 Hz). Determine the energy stored in the inductor at t = (1/180) s, assuming that this energy is zero at t = 0. Now when i tried to solve it, this is what i did: ω = 2∏ f = 2∏(60.0/s) = 377 rad/s XL =...

Ive never understood why outlets have 3 holes. The two at the top are the voltage in and voltage out, correct? So why is there a ground if the current already has a way to return to the voltage source through the second hole? Also, i am assuming that power lines have two cables coming from a...

Homework Statement A circuit is constructed with an AC generator, a resistor, capacitor, and inductor as shown. The generator voltage varies in time ε=Vb-Va=εm cos(ωt), where εm = 122.5 V and ω = 10.35 x 106 radians/second. The resistance of the circuit is R= 132.1 Ω. The inductance is L=...

Are they shining brightly inside the device when used to convert ac?

Homework Statement A circuit is constructed with an AC generator, a resistor, capacitor and inductor as shown. The generator voltage varies in time as ε = Va - Vb = m*sin(ωt), where m = 24.0 V and ω = 187.0 radians/second. At this frequency,the circuit is in resonance with the maximum value...

I was recently informed that AC is the preferred method of transmitting power because it suffers significantly less power loss going from the generating station to where ever it needs to go when compared to DC losses. In my introductory electricity class we learned that power through a given...

We talked about AC circuits and phase shifts were discussed. Voltage changes "lag behind" current changes so that's how we get phase shifts. It's like a sinusoid so fine. Then we talked about impedance. There's a real and "imaginary" component to impedance, graphed on x-axis and y-axis...

I have been tought several times that if an asynchronous induction motor is overloaded, so that the rotor speed goes below where the maximum torque point is, the motor will become unstable, and simply stall, even if you unload it. Why does it do that? fx. here...

Hello everyone, For my physics class, I want to build an AC motor with styrofoam, magnets, screws and magnet wire. So far, I have built a cylinder of about 2.5" of radius and 1" in height with eight magnets (strengh 6/10) around it. Each magnet is glued on the side of the cylinder...

In an AC circuit, the average power dissipated is given by P=VIcos(\phi). Does that mean that in a highly inductive, or highly capacitave, circuit where \phi approaches \pm \pi/2 , the power can be made arbitrarily small? Even if a resistor were present? Does that mean it wouldn't heat up at all?

Recently, I've been studying AC circuits and have developed a couple questions. I think I worked out an answer to the first, but I don't know about the second. First, since light bulbs in houses are powered by AC current, why do we not see them flicker? Assuming they obey Ohm's law, the...

Pretty much every proof of this I've seen uses the axiom of countable choice at some part or another, and I never got why, since it's pretty cumbersome. Here's the sketch of a proof I wrote for the "fact" that a countable union of countable sets is countable: Let \ P:=\{\pi\in\mathbb{N}|\ \pi \...

Homework Statement Given an AC Voltage that varies in time according to the equation: v(t) = 100 sin(250t) (i) What is the frequency of this waveform? (ii) Calculate the time for one complete cycle of the voltage? (iii) Calculate the instantaneous value of the voltage at time =...

Homework Statement I've attached the question. So I'm not sure which method should be used to solve this. I was thinking superposition, but the voltage supplies are are both at the same ω value. Homework Equations v(t) = Vmaxcos(ωt + \phi) ZL = jωL ZC = 1/jωL The Attempt at a Solution convert...

Hello, Why do we use KVL in Ac circuits ?! or to be more specific is it accurate to use it in Ac circuit , just the same accuracy as using it in Dc ?! Doesn't the current that pass through the circuit itself make it's own variable magnetic field , which crosses the loop of the circle ...

Hello, My electrician had to disconnect the ground wire from mains distribution box a day ago. And he forgot to attach it back. I did not know it was un-attached. Then in the evening, I touched my computer and got a shock. I used a screw driver type phase tester and checked the ground part of...

Homework Statement Ok so before I begin I've done my share of research and have had no luck as people seem to be moving to calculators for answers these days. I know my rectangular and polar conversions in AC but I haven’t done too much work with complex numbers. I basically have two...

Homework Statement I know that in a RC DC circuit the time constant is R*C. But what about a RC AC circuit, is it the same time constant? Same goes with RL AC circuit, is the time constant R/L? Thanks!

Hello! I found a cool site to buy odds and ends electronics. It sells RF wireless remote systems equipped with relays. With halloween coming up this will be really fun to play with }:) . My question is, the description states the relay output is 125V VAC but if can't I run VDC through it...

I'm trying to figure out how multiple AC sources which are in phase would be able to be used sequentially to power a load. This all started as I read some literature about solar PV panel systems which had a wiring diagram to tie output from the inverters directly into the electrical panel split...

I post to this forum, because I want to analyze this phenomenon with the aid of those who may understand the various nuances of scientific theory, by which such a thing could occur. I do not feel that posting to a forum dedicated to audio/video would yield quality results. This matter...

Homework Statement In a model ac generator, a 500 turn rectangular coil, 8.0 cm by 20 cm, rotates at 120 rev/min in a uniform magnetic field of 0.60 T. (a) What is the maximum emf induced in the coil? (b) What is the instantaneous value of the emf in the coil at t = (∏/32)s? Assume that...

Hellow guys! I find this concept really confusing, if the bulk resistance of a diode is an approximation of the I-V characteristic curve for a diode, Why then is that bulk resistance compared to ac resistances of the same diode at a particular operating in calculated values, seem not to...

Homework Statement Hello, I've recently finished an experiment on forced damped simple harmonic motion with a CLR "capacitor , inductor, resistor" circuit with the aim to measure the resonance frequency of the system, using a family of graphs for which each the resistance is varied. voltages...

I found this motor at a thrift shop and got it for free. I wired it up and found that it pulls a surprising .45 Amps. It also generates an amazingly effective magnetic field around it. I am scared to touch it with both hands. It seems to have a small transformer... Probably makes some mean...

need lectures of good references of AC synchronous and links if you have ... and I wonder why the field of it is DC ?

How is the compressor speed controlled in a car air conditioner, in compressors driven by engine moved belts? Is temperature controlled just by on/of of the solenoid clutch? Electric air conditioner (automotive), not driven by (directly) by engine, is widely used today? Another question, not...

I need to perform mesh analysis using complex numbers on an AC circuit. My issue, is I don't understand how to do this. The circuit contains only one voltage source, where we have only been taught how to perform a mesh analysis on a circuit that contains 2 voltage sources. Can someone show me...

To increase a DC generator's turning effect, we increase the number of turns of the coil. How does this increase the turning effect? Will it concentrate the field lines or will the force acted on each coil be added to each other to increase the force on one armature? I think both happens because...

Hi, I'm investigating maximum power transfer in a AC circuit. I understand that for maximum power transfer the reactance both cancel each other out and the value of the source resistance and load resistance have to be equal. I have also found some formulas to prove this. what i would like...

I hope someone can help me. I have an old 30 HP motor that I need to get working...if possible. It is a 12 wire Toshiba, dual voltage. 230V 460V. To wire for the low voltage the nameplate says: connect wires 4,8,10 and 2 to supply 1. Wires 9,5,11 and 3 to supply 2 and Wires 6,7,12 and 1...

I've been given the following problem (attached), not sure how to tackle this one, do I use mesh/node analysis and super node analysis, or can I find the v in the loop with the dependant voltage source then use that as the supply to the second and third loops? Not sure, any help would be...

Turning FETs "off" in presence of AC signal at Drain or Source Hello, I have a very interesting problem that surprised me, and as of yet have not been able to find a solution for. I have two coupled coils. One is being driven by a pulses. The other coil has FET switches to switch the...

Hi! I was wondering if there are any guides with problems and exercises relating AC circuits (capacitors and inductors), circuits with phasors and real, reactive, and apparent powers. I do not need the answers, I just need a selection of exercises to study from there.

Can we Earth ground AC and DC voltage? would this effect the components on the system?

Hello, I'm looking to amplify a very weak AC signal using op-amps. The problem I'm running into is that I can only operate using a +5V supply voltage, no negative voltages. My AC signal is about 5mV and I need it to be about +2.5V. The AC signal is initally DC baised and is at +3.5V, so I put a...

Homework Statement http://session.masteringengineering.com/problemAsset/1127287/7/Probs._454_55.jpg Find the moment about the axis AC. F=<7,12,-6> Homework Equations MomentAC = Uac dotted with (Rab X F) Uac is the unit vector from a to c The Attempt at a Solution Uac=<.8,.6,0>...

Homework Statement For an AC generator, my teacher told us that when turning it, you will slowly manage to turn it at a constant speed only because of the induced current causing a force in the other direction to the turning motion. Why is this so? For a DC motor, my teacher told us that after...

Hi there, in this youtube tutorial about AC circuits http://www.youtube.com/watch?v=JiLdrAHBBRc&feature=plcp at about 4:08 It's supposed to be z=√(R^2+(XL-Xc)^2)) but in the example she does Xc-XL, is there a reason for this or is it a mistake in her working??

For doing modal analysis of suction and discharge side of an air-conditioning unit, is it needed to consider the inside refrigerant?

I want to controll ac motor using pwm.sir told me for that you required volage controller and phase controller.if voltage is controlled by pwm so why i want to use this phase and voltage controller?

Having carried outan AC Resonance experiment recently, I find that I have missed a simple step in the procedure- or left it out of my lab book - grrr! For a parallel RLC circuit I was asked to observe voltage across the inductor (coil) at a constant current setting. I'm assuming the trace to...

It is said that toroidal inductors/coils (see http://fa.tu-sofia.bg/te/Brandisky/images/toroidal_coil.jpg ) that are perfectly axially symmetric will completely confine B fields. That is, the B field inside will be nonzero and will circle the toroid, but the B field outside the toroid will be...

I was just reviewing AC circuits and the diagram shows that the voltage changes in AC, it goes up and down and on the diagram is shows the current goes one way then the other. But in AC, does the neutral become live? I thought the red was always the live wire! but according to the diagram...

Hi ! I want to amplify the output of my hall effect current transducer ( CSLA2CD ). The output of my hall effect sensor is 15.6mVac. And I used a dual rail op - amp to amplify this small ac voltage which the gain is 101 ( as shown in the schematic below ). I tried to simulate using multisim...

I am currently using a 600HP DC motor for an extruder application and I am exploring the idea of switching to a 600HP AC motor. What kind of energy savings/efficiency can I expect if any?

As the tittle, I am looking for off line switching supply of about 400VDC output. Anyone know who make this? Thanks Alan

1. The problem statement. AC voltage is expressed as 240 cos(2765t - 45°). Im trying to find the: Peak Voltage: RMS Voltage: Average Voltage: Peak-to-Peak Voltage: The Attempt at a Solution Peak Voltage: 240v RMS Voltage: 170v Average Voltage: 0v Peak-to-Peak Voltage: 480v...

Lets assume you're given { 3x }^{ 2 }+8x-11 And you want to factor it. With the AC method you multiple 3 and -11 giving you -33. Then you find the factors of -33 that add up to 8. 11 and -3, in this case. Then you rewrite the quadratic as { 3x }^{ 2 }-3x+11x-11 From there, you...

I understand AC is economic for transportation and easy to produce from converting mechanical energy into electrical energy. However, why don't electronics turn on and off because of this alternating nature of the current? For light bulb, maybe it does turn on and off and our eyes don't have...