What is Ac: Definition and 1000 Discussions

How to draw a phasor ? Homework Statement Two alternating currents are applied out of phase with each other. One is 4 volts and the other is 3 volts 27° out of phase. These can be written as (4, 0°) and (3, 27°) Homework Equations a)draw both phasors b)draw the combined phasor...

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I'm building a wire strippers by cutting a hole in a piece of 2x4 which has a blade on the bottom of the hole. I want to use a motor to pull the wire threw by using a motor a gear and a strip of metal. The strip of metal clamps the wire down on the gear which is turned by the motor. I was...

What type of digital signaling is more efficient, digital DC or digital AC? With digital DC, the square-wave signal is only between a (+) value and 0. With digital AC, the square-wave signal is between a (+) & (-) value.

Hi all, I've been struggling with an issue for a while and have finally admitted that I am in over my head and need some help :) here's the situation. I have a string of variable capacitors; all in parallel. let's say for this example that there are 100 V...

I have a situation where I see spikes (with ringing) on the output of DC power supplies whenever something AC powered is switched in the room. The spikes change in magnitude; they can be as bad as 3 volts peak-to-peak; I suspect they change "randomly" because they are related to when the device...

The Scenario: Two long parallel conductors A and B are carrying an ac current with a wave length of λ. The conductors are separated in distance at all points by λ/4 and the ac current phase of conductor A leads the ac current phase of conductor B by λ/4 at all points mutually at right angles...

Hello everyone! This is my first time posting here and I hope I can make a good first impression, and I apologize for the lack of links because of this being my first post. Currently I am working on a project for my grandfather's engineering business, and part of this project is designing a...

Hea, We're building a custom power supply to power some servo controllers (Copley Control Junus). Unfortunately we don't have any 7.5 kw power supplies to power these things, and don't want to spend the 5-10k necessary to get them. We're taking mains, isolating it via...

Can someone explain me why dc motor is self starting differ of ac who is not self starting motor?

Given that: E = hν where E = energy of a photon h = Planck's constant = 6.626 x 10-34 J·s ν = frequency Why is it that the energy (electromagnetic waves) in AC electrical circuits does not include frequency as part of the formula? eg. \begin{array}{l} P =...

I get that collector current is fixed so as collector current goes up, the voltage drop across the collector resistor goes up and the collector-emitter voltage goes down. Which is why it is basically zero at saturation. But for ac it is not zero but negative when input is positive. why is this...

What would be the direction of the current from the mains till it completes its one full path and the appliance used in the circuit starts working? See attached image.

I am supposed to discuss the benefits of having high number of magnetic poles in ac generators with constant frequency. From formula it is obvious that the higher number of poles the lower the speed of rotation. But is there anything else, or what is the benefit of lower speed? The only...

Hello! I´m currently reading Halmos - 'Naive Set Theory' on my own and try to solve the problems that the author has supplied by myself. When it comes to the chapter of Zorns Lemma I feel a bit confused and have not manage to solve the problem in the end of the chapter.. In other words to show...

http://img521.imageshack.us/img521/8044/mycircuittt.jpg Considering VP to the ground... I draw only the negative pulse to define it, right?

Homework Statement Can somebody explain how it is possible to charge a capacitor using ac voltage? The way I see it is the capacitor wouldn't have time to charge as the voltage is constantly switching. In the case of 60Hz - 120 times a second. I seen a schematic of a tesla coil where the...

Hi, I have a circuit with a pot connected to an 26VAC signal through a diode and to ground... i.e. there is a half wave rectified signal across the pot. I'm then measuring the voltage off the wiper. I'm looking through some peoples work, and they write the max output voltage is...

Hello, I have simulated AC electric field in multiple (in fact 3) media with COMSOL, a multiphysic solver. The simulation took place with different frequencies of applied electric potential. Media have different conductivities. At lower frequencies, every thing is ok, I mean, electric...

I built an array of 14 LED's the 20,000 mcd's ones maybe drawing 25 ma at 3.3 volts with each two LED's powered from 125 volts AC then to a .22 mfd capacitor in series feeding a full wave bridge rectifier so there are 7 capacitors and seven full wave bridges feeding all 14 LED's and they draw 6...

I do not work with this type of conversion so I am not familiar on how to understand so here is my problem I have a electrical supply line putting out DC current at .6 amps by 17 volts which equals 10.2 watts here is my question if I take a 125 volt AC bulb rated 10 watts will this be enough...

Hello... The concept that resistance can be for a dc supply only and not for the ac supply coupled or superimposed to the same circuit, is something i don't understand to this moment... I first realized this in diode systems... where i saw bulk resistance for DC and dynamic resistance for AC...

Hello I want to calculate field of the Solenoid Coil with AC current. For a DC current field is calculated easily from the BiotSavart. What is the process for AC current? Get the L value with RLCMeter in operating frequency? Is there an equation to get the field with...

Homework Statement Just before reading, i am posting this as this question seemed way to easy to solve in my assignment, problems aren't usually this easy ! haha. I need to find V0, i originally just found the voltage at that node using KCL which was straight forward, but in my lecture notes...

I have a situation on a dashboard where the dashboard itself (metal) is the “ground” and two different items require a different voltage. One item requires 5 volts and the other requires 25-28 volts. Each of these items has a single lead. How can I attach two different ac power supplies when...

Homework Statement A radio tuner built by connecting an L=0.58mH inductor and variable capacitor in series with an antenna. The driving voltage is provided by the radiowaves that pass through the antenna, and the total internal resistance of the circuit is R=2.6Ohms. The variable capacitor is...

Not being an electrical engineer, I have always wondered how sources of AC power are matched when joining a common grid. I assume the power is generated at 60 hertz from each source but how is the match made so sources are in phase with one another? For instance, suppose an individual could...

Hi, I know that existence of AC and DC currents but what exactly the same with AC and DC potential difference. Of-course it was very basic question and i apologize if it annoys any. Please explain the difference only in terms of voltage. Thank you.

Hey all, I'm just working through the london theory of superconductors. I've dervied the london penetration depth, the distance for the amplitude to drop by a factor of 1/e... Seems simple... Now my book talks about applying a an ac magnetic field to a superconductor. How would the field...

Hi All, Currently Iam working on a project where I have to superimpose High frequency component on AC mains 240V 60HZ. ( Its imposing Ripples in mains voltage... as happens when voltage is generated from a Petrol generator). Need some help how would i do this ? Thanks in advance. Shakey...

Hello, I am new to this site and thought I would give this a shot. All my experience is in low volatge DC circuits and don't have a whole lot of experience dealing with AC but I am trying to learn. My boss and I are working on an experimental generator with 24VDC input but AC output...

So I've been trying to figure out what I'm doing wrong regarding a theoretical aspect of this lab. I've used both ideal analysis and experimental analysis and can't figure out if I'm doing this right. The circuit is shown produced in Multisim below: The function generator produces a...

This is quite a frustrating problem for me so hopefully somebody can describe it in such a way that it settles in my mind. It is the concept of voltage and current being out of phase. Inductors are frequently described as responding to changes in current but does this really make sense...

Homework Statement An A.C. voltage, V comprises of a fundamental voltage of 100V rms at a frequency of 120Hz, a 3rd harmonic which is 20% of the fundamental, a 5th harmonic which is 10% of the fundamental and at a phase angle of 1.2 radians lagging. i) Write down an expression for the...

Homework Statement This is more of a conceptual problem I'm having difficulty getting my head around. What is the difference between Iaverage and Irms for a rectified and non rectified AC circuit? I know Iaverage=(2/π)Imax while Irms=(1/√2)Imax but I don't understand why they are...

Homework Statement An AC current source, 1 ∠0° A, with angular frequency 1 rad/s is to be applied to the input terminals of the circuit. Circuit is RLC, the current source is in parallel with a 1F capacitor which is in parallel with a 1H inductor which is in series with a 1Ω resistor. I...

Hi All, I'm trying to visualize the flow of electrons in an AC circuit. DC is pretty simple as I can imagine the electron moving from point A to B. AC on the other hand confuses me. If there's a constant switch of polarity one would imagine that the electron would move forward as the...

Hey guys, Just need some help with this question, It asks for the answers to be in circuit parameters: http://tinypic.com/r/k0k2ed/5 For some reason I don't think my answers are correct as I'm finding it hard to make sense of my answers to the questions. a)Find the voltage Vab (magnitude and...

consider two circuits: In circuit A the signal form mic AC (very low amplitude ) is combined with Vbb(to drive the BJT), as the two voltage sources are series they adds up and its amplitude increases and it is passed to bjt and then to loudspeaker. in circuit B the signal form mic AC (very low...

Single phase AC motors generate a rotating magnetic field using two inductors which are turned on and off sequentially. The second inductor is connected to a capacitor to change the phase angle of the electricity delivered to it. When the supply current is turned on, one inductor is turned on...

I have been going through the ac signals coupled by a capacitor to a dc network.. Using superposition principle.. for solution it was shown that both bulk resistance and dynamic resistances for the diodes used are required... Why is this happening.. Since to what i know bulk resistance is...

AC vs DC! The intent of this post is mostly for aspiring students: When working with one of my students recently….I notice he tends to freak out between the difference of AC and DC……Like they are two completely different subjects. He says one has a frequency and the other doesn’t. I say not...

Homework Statement A circuit contains two elements, but it is not known if they are L, R or C. The current in this circuit when connected to a 1.20×101 V, 60.0 Hz source is 4.70 A and lags the voltage by 4.20×101 degrees. a) What are the two elements? (Answer A,B or C) CL CR LR Homework...

Homework Statement how can i transmit ac signal to μC to further ADC? Homework Equations The Attempt at a Solution can i use dc offset?

I had always thought that a capacitor with a dielectric transmits AC precisely because it polarizes in response to the applied field. To tell you the truth, I realize now that I had two different views on how this process works: One: the AC is oscillating on both sides of the dielectric...

Three uncharged capacitors each of 1uF are connected in parallel and the combination connected to a 100V power supply via a 1MΩ resistor. After 2s the capacitors are removed, connected in series and the new combination allowed to discharge through a 10kΩ resistor. Find the discharge current...

I was wondering if I may interprete AC current as a tranverse wave trough copper as medium. So this wave behaviour has a general wave-form written as: \zeta(x,t)=\zeta_{0}sin(kx-\omega.t) This is a solution to the partial differential equation: \frac{\partial^{2}\zeta}{\partial...

I wish I had a plot of voltage on the X-axis and danger level on the Y-axis for AC and DC. I was talking to an engineer at work, he was telling me that DC is more dangerous at high voltage. I said I disagreed with him but did not do into detail as to why I thought so. I did say that I've...

I am trying to make a .4 Tesla AC (50Hz) magnetic coil. Originally I used ID-38MM, OD-155MM & Length of Solenoid 50MM. Using 3.5MM X 1.5MM wire 380 Turns. I get 0.27 Tesla at 75Amp. but the wire allows me to work only for around 5 Min with Forced air cooling. I do not know the relationship how...

Homework Statement Chain/product or quotient Homework Equations v=4sin^3 (4t) The Attempt at a Solution NB:@ Means teta(spelling might be wrong) 4sin^3 (4t) = 4sin (4t).sin (4t).sin (4t) using sin^2@=1-cos 2@ /2 v= 4sin (4t). (1-cos 2@ /2) = 4sin (4t)/2 . 4sin...