What is Ac: Definition and 1000 Discussions

Hi Forum, once again I seek your help I have a very good understanding of rotating magnetic field due to stator, armature reaction, and the phasor diagram. from energy point of view it is very clear that if Gov increases, while output voltage remains locked by the gird, Amp will increase...

Hi, Thank you for reading this. I understand the functioning of DC current. You create a potential difference and the electrons flow from the power source through the electrical appliance (thereby, powering it) and flows back, completing the circuit. But, in AC, the electrons...

I have worked on an example earlier today. It's the section on BJT Amplifiers. I have been studying the sub-section on Common-Collector Amplifier. I've come across a rather peculiar formula, which has not been mentioned anywhere in my prescribed textbook besides a worked example. Here is the...

When a circuit is being alimented by AC this means that exist in the circuit a voltage source that is generating the AC or exist a current source that is generating the AC?

Apologize in advance for the long post! We are in this particular situation and, being a novice with electrical- related issues, would greatly appreciate opinions here. After a year long search, we found this nice home in Texas meeting all requirements my wife and I were looking for, and at...

Hello. I'm trying to design a AC to DC LED driver with PWM dimming. I have a design that I can use with the LM3406HV but I would like to design something that I can wire up 110V AC mains line. With the LM3406HV I need a DC power supply. I was thinking about using a switching power supply but if...

Homework Statement I have the network attached below. I need to find the open circuit voltage and short circuit current between A and B and then use these to find the Thevenin equivalent for the circuit. The Thevenin equivalent voltage is of the form VTsinwt and the equivalent impedance is...

Hey, I don't if this is the right place to ask ( it is not a homework question but just a curious one about what i read in my textbook).. How can AC circuits even work? If the drift speed of an electron in a normal household wiring is something in the micro m/s and it reverse every 1/120 per...

Homework Statement Image Attached Homework Equations Thevenin, Series, Parallel The Attempt at a Solution j10(12-j34) / (j10+12-j34) = (340 + 120j) / (12/j24) 1.67 + j13.3 or 13.44∠82.4° Now why can't I just use this equivalent resistance and multiply by the current source (22∠30°)...

I'm learning AC and theory says that the polarity of AC inverses.. even the name says 'alternating current'.. now what about the live and neutral? does the current goes from neutral to live and and vice versa? Some people says that only the phase inverses, but the current is always from live to...

Homework Statement a resistor of 1000 ohm is connected in series to a capacitor and ac supply of frquency 50hz, if the phase diffennce of voltage supplied and current of circuirt is 30 degree, what's the capacitance of capacitor? the V max and I max in not given , how to do this ? help...

In an AC circuit, we know that the polarity inverses, and what i know is that the flow of current also will therefore inverse.. which means that the live will become negative and the neutral will become positive.. What i can't understand is how the polarity inverses but the live is still the hot...

Homework Statement A voltage source e(t) = 50 sin(2000t + 30°) V supplies the current i(t) = 0.5 cos(2000t) A in a circuit. Find the impedance in the circuit, in both polar and rectangular form. Is the circuit inductive or capacitive? Homework Equations The Attempt at a Solution...

Homework Statement A1 = 5A, A2 = 4A, A3 = 3A. V = 120V a) Given the circuit above, find A4 b) Find the angle between E and IT. Draw a diagrammatic (?) and find the power in the circuit. c) Find the values of R, L and C. Homework Equations The Attempt at a Solution...

So i started studying about AC circuits and i tried solving an exercise.The problem is that not only i am stuck,but also i am not even sure that what i have done so far is right and follows the right logic.So some quidance on this would be appreciated. Here is the problem...

A capacitor in an AC circuit. What is the amplitude of the current?? Homework Statement I really do not know how to approach this problem. What confuses me is that when calculating the % error I'm suppose to have a theoretical or accepted value and a measured value. So how do I determine...

Homework Statement The AC circuit is the following: Vin = 10√2*sinωt V R = 5 Ω L = 5 mH C = 100 µF a) what is Vout when the frequency (f) is 100hZ Homework Equations The Attempt at a Solution After two weeks of spring break in addition to Easter holiday, I'm well...

Okay so I have been working on a problem for practice for an exam and this one question is really pissing me off. I can't find what I am doing wrong and I've redone it about five times. The question is asking for the admittance of the circuit and the answer is given as 2.29 S at an angle of...

Hello, I'm in Arizona and was looking to hook up some PV panels directly to the air conditioning unit pump. Is this a reasonable goal? I figured that I could disconnect the AC unit from grid power and then hook up the solar panels/inverter to the AC unit, but is it possible to have the...

Hi All I am asking this question as a mechanical engineer, so please bare this in mind if you have the time to post a reply... I have a basic DIY type cement mixer that has given up today. It is a AC 230V model with the most basic of drive setups (pulley and drive belt attached to the...

Hi all, I would like to make a switch for an AC signal (on off ,ie, high impedance and low impedance). The switch should have less than 1 ohmn impedance. The signal can range from 1-100Khz and the signal will be 50Vrms. I tried to use mosfets, but they do not block the signal completely...

Hi! I'm in a place where electricity goes out frequently; as a result I got a UPS which is powering my computer the total power input of which is less than 200W. The UPS is 300W or 600VA. The transfer time (time to switch from AC mode to battery mode) of the UPS is around 4 ms; but in that...

Homework Statement For vi(t) =V0 cosωt, obtain an expression for vout(t) in the circuit below and then evaluate it for V0 = 4 V, ω = 400 rad/s, R = 5 kΩ, and C = 2.5 μF. Homework Equations The Attempt at a Solution For this problem, I am having difficulty taking that second term...

Homework Statement The average power dissipated by a resistor is 4.0 W. What is the average power if the resistance R is doubled? Homework Equations P_{rms}=I_{rms}^2R=I_{rms}V_{rms}=\frac{V_{rms}^2}{R} The Attempt at a Solution I am told the answer is 2.0 W. But here's what I am confused...

Homework Statement Apply nodal analysis in the phasor domain to determine ix(t) in the circuit below. Homework Equations The Attempt at a Solution This is super confusing to calculate in the phasor domain, I was just wondering if anyone could check my calculations and see if they...

Homework Statement In the circuit below, what should the value of L be at ω = 10^4 rad/s so that i(t) is in-phase with v(t)?Homework Equations The Attempt at a Solution I am a little uncertain exactly what is meant by i(t) being in phase with v(t). Do I assume that both are cosine functions...

Hi! I have been studying AC generators. I am confused about why there is no current when the armature is perpendicular to the magnetic field (when it is vertical). Also, what is the purpose of the brushes? Probably a really obvious answer, but it is confusing me. Any help would be...

I understand that an inductor acts as a closed circuit to DC because it's just a coiled wire but why doesn't it act the same way for AC? What does it act as in AC?

Homework Statement Compute values for R and C such that the total series impedance Z=500\angle(-36.1o) when f=10kHz. Homework Equations ω=2\pif KVL ZC = -j*(1/(ωC)) = 1/(jωC) where j=\sqrt{-1} The Attempt at a Solution Seems like a pretty straightforward problem, I seem to...

Homework Statement Homework Equations The Attempt at a Solution The text in the black box looks wrong to me. The method below is how I would do it. Why is it wrong? $$To\quad maximize\quad power,\quad \overrightarrow { Z_{ L } } =\overrightarrow { { { Z }_{ th } }^{ * } } \\ \\...

In my class we did an experiment where we measured the flicker frequency of an incandescent bulb and a CFL bulb (powered by a 60hz wall plug) using a photodiode and a oscilloscope. We were then asked some questions about the sinusoidal curves that were produced. 1. The incandescent...

My textbook has this excerpt: I am not sure why it refers to Example 10.6 as that is unrelated. I don't understand to be honest. How can you calculate the Thevenin equivalent at different frequencies? Let us say that you have two voltage source: v1(t)=10cos(5t) and v2(t)=10cos(2t). So how...

Here I have a problem I am dealing with. I answered the question and have it shown on the picture but I would like a double check on it as I think I am getting wrong values. The circuit is shown at the top of the page. If you can't see the values are 10 ohms for the resistor, 3.2 mF for the...

12 volts DC will travel thru a Diode connected to 120 volt AC , but will it put any load on the battery? John

I'm a mechanical engineer and am learning about the different refrigerants used. 2 of them seem to be the most popular- R134a(C2H2F4) and R1234yf(C3H2F4). Why is it that R134a is rated at a Greenhouse effect(GWP) of 1430 where R1234yf is rated at a GWP of 4? Both refrigerants produce...

Hey, I hope I don't bother any of the serious electrical engineers, but I was wondering if anybody could help me with a project I'm working on. I want to build a generator that I can attach to my stationary bike that will charge my phone. It has a very simple design, two permanent magnets that...

How did Hertz do it with his spark gap transmitter?

I want to replace an adaptor for some appliance. The part that is sold in an official website of the product is expensive. So I'm looking for compatible models. Is it usually OK to only consider matching Output Voltage and current? S018QU2400050 is written on the apator. I think 24 stands...

Homework Statement Find nonzero matrices A; B; C such that AC = BC and A does not equal B Homework Equations None that I know about. The Attempt at a Solution I'm not sure where to start, I would like to know how to complete this problem.

I was a little surprised to find out that the IEEE recommends using "ac" and "dc" for alternating/direct current rather than "AC" and "DC." (Google "Recommended Unit Symbols, SI Prefixes, and Abbreviations - IEEE") Apparently non-capitalized is the "correct" way but I've mostly seen them...

Homework Statement I just learned that in a DC motor you use a commutator to convert the AC current to DC. And in my other course I learned that you can convert AC current to DC using a rectifier circuit. If this is the case, why don't we use a rectifier circuit in a DC motor to convert the AC...

Hello I know what is AC signal and DC signals purpose.. but may I know how to convent AC signals to DC signals to feed into the PIC?? Help pls

Hi, A local alarm company has given me a quote, and they want to connect the power to the alarm as follows: The 30VA 16VAC transformer is connected to a 7ah 12V battery. The battery apparently can run in AC mode, this was news for me. The alarm requires AC power, and is connected in...

Homework Statement For the circuit in question1above: R=(3.74x10^2) (Ω), C=(3.8700x10^-7) (F), f=(4.610x10^3) (Hz) and the peak amplitude of the voltage of the source (ES)=(6.185x10^1) (V). Calculate the instantaneous value of the voltage across the capacitor at t=(4.110x10^-5) (s) after the...

I am half way through my Electrical Engineering program and have only just started to learn about AC circuits and inductive loads but I did a little reading and went off to try a simple project on my on. A company I work for wanted a switch to turn off their large refrigerator for certain...

Hi everyone i am Julius a 400L student, this is my first post as a new member of this great forum. Please,i want to know a step by step practical guide on how to convert AC to DC , i join this forum for me to properly learn (PRACTICAL) from the masters here and it will be my pleasure if i can...

Is there a simple way to "make" static electricity from an AC outlet? Looking for a way to make my hair stand (what is left of it) on its end for an experiment. Thanks for your comments in advance.

What will happen in a ferrofluid in an elastic cylindrical tank when subjected to high voltage alternating current? Is it will expand and then back to its normal dimension periodically because of repulsion? The diagram on the attachment is the set-up, all answer will be appreciated. Thanks

Hello, I want to design an AC voltage indicator. So i designed the circuit attached, but now i am trying to calculate the value of the resistor R1. I have the following problem: 1- The voltage should be given at the terminals of the optocoupler. 2- The minimum current that should flow...

Often I'm reading on other sites that if a 2 pole 3600RPm (synchronous speed) motor were connected so that the ratio would lower the speed to the same as a 4 pole (2X) and so on with 6 pole (3x) the output HP will remain the same. However the larger the number of poles the larger the motor and...