Ac circuit Definition and 199 Threads

Homework Statement Given the circuit of sinusoidal current (attachment 1) with given data: \underline{Z_3}=200(3-j4)\Omega, \underline{Z_4}=100(3+j20)\Omega, \underline{Z_5}=100(3+j4)\Omega, \underline{Z}=100(2+j5)\Omega, \underline{I_{g2}}=-10(2-j)mA After the switch is closed, the increment...

Homework Statement Given the circuit of sinusoidal current (attachment 1) with given data: \underline{E}=100V,\underline{E_1}=40V,\underline{Z}=(10+j10)\Omega,\omega=10^5rad/s,L=1mH, C=0.1uF. Find \underline{I_L},\underline{U_{16}}, active and reactive power in the branch 2-5. 2. The...

Homework Statement Both diodes are ideal. Answers: (a) Vi (b) -Vi (c) -2Vi (d) none of the above Homework Equations Q=CV The Attempt at a Solution 1. For t=0 to Pi: Cap1 and Cap2 are in series and hence Q1=Q2, therefore Vc1 = Vc2. From this we get Vi = Vc1 + Vc2, hence Vc1 =Vc2 = Vi/2. 2...

Hello everyone. So i live in Lebanon, and since a long time now we have constant power cuts, almost half the day each day. For that the Lebanese made up a system in which each neighborhood has power generators providing electricity to the residents when the power is out. Usually the owners of...

Homework Statement Homework Equations V=IZ[/B] Zc = 1/(-jwc) Zl = jwc w = 2(pi)*f The Attempt at a Solution I'm teaching myself circuit analysis, and it's been rough. Ultimately, I been able to mostly figure everything out, but I've ran into a wall with AC. The main problem I am having...

Homework Statement Find the currents through ##R_3, i_1(t)## and ##R_2, i_2(t)##. I attached a diagram of the circuit (diagram.pdf). In the original diagram the currents I'm trying to find is marked going top to bottom, there's also no directions on the voltages in the original diagram but...

In all tutorials I have read on tesla coils, they have said to use a capacitor spark-gap configuration, to create a tank circuit. I want to know exactly what this means, and what is its purpose. I am not going to build a Tesla coil, I am nearly just interested in the science of it.

Since the resonant frequency of a tank circuit, is completely adjustable, and controlled by the value inductor and capacitor you use, I was wondering if it had any other uses, other than increasing its impedance at its resonant frequency. Can if be used to produce ac signals of its resonant...

Homework Statement A capacitor has a peak current of 240 μA when the peak voltage at 250 kHz is 2.7 V . Part A What is the capacitance? Part B If the peak voltage is held constant, what is the peak current at 500 kHzHomework Equations Xc=1/wC Vc=IcXc The Attempt at a Solution I rearranged...

Homework Statement Three receivers, with complex impedance \underline{Z_1}=(125+j375)\Omega,\underline{Z_2}=(700+j100)\Omega,\underline{Z_3}=(500-j500)\Omega, and two sinusoidal current generators of effective values I_{g2}=40mA and unknown I_{g1} are connected. When the switch is open...

Hello, In my textbook, it says that if we have a pure inductor connected to an AC source, the average power is zero. It explains that this is because the energy is used to create a magnetic field for the inductor and then it is extracted to the AC source. So how is it possible for the...

I haven't used any book for AC circuit analysis yet. I have learned the basics of phasor diagrams which my teacher taught in the class (We were only taught series combination of LCR circuits). Can anyone suggest a book to learn more about circuit analysis (like source transformations, Norton's...

Homework Statement Find the peak value of current through the AC source of the following L-C-R circuit, if peak voltage is ##V_0## and angular frequency is ##\omega_0##. Homework Equations I have learned Vector algebra and calculus (single variable). I was taught how to use phasor diagrams...

The question is: The voltage source in the above circuit is a sinusoidal AC source with constant amplitude and constant phase shift but an adjustable frequency. Calculate the frequency ω at which the phasor current I...

Homework Statement A sinusoidal supply defined by ## v(t)= 325.27 sin(314.16t+\frac{\pi}{6}) ## is connected across a coil of resistance 25Ω and inductance of 0.5 H. The instantaneous value of the current at 2.968ms is 13.13 mA 21.6 mA 87.8mA 13.8mA Homework Equations ## i(t) = \frac{v(t)}{Z}...

In a branch I have to find complex power which is having current 19.41<-37.3 A and impedance 4+j3 Ω What I used is i2z and I was getting 1489.85 - j1152.74 W. This is wrong but I don't know how because by this site the answer was different...

I have completed a small project of ac circuit analysis on intel galileo in arduino. I want to make a GUI now. How should I proceed? I know C and a little C++.

It's pretty easy to find the "working principle" of surface capacitive touchscreen like http://www.elotouch.com/Technologies/SurfaceCapacitive/howitworks.asp Roughly speaking, I know that A surface capacitive touchscreen has a conductive layer to which some electrodes are attached The...

Homework Statement SOURCE: v(t) = (311)cos(314t) [v] IN SERIES WITH: R = (0.3) [Ω] L = j(0.7) [Ω] "load" = 2.5 + j(1.0) [Ω]Homework Equations Find the instantaneous current, and the phasor current. The Attempt at a Solution (1.) I first found the frequency of the source: (314) / (2*pi) ≈ 50...

Homework Statement Homework EquationsThe Attempt at a Solution I am surprised that this question came up, I haven't learned ac circuits yet. I don't know how to solve this. I just added both values and current and divide it by two, which gives me 1.5A, since I thought it's the average but I'm...

If drift velocity of electrons changes in AC, how does electricity flow through a circuit to then lose potential energy to the devices in the circuit? Also considering the change in direction, does that mean that the live wire and neutral wire also switch roles in AC mains? I am very confused...

Homework Statement *(Problems attached as images)* For first problem: ##\cfrac{|V_2|}{|V_1|} = \cfrac{1}{\sqrt{4+(\omega RC)^2}}## For second problem: ##\cfrac{|V_2|}{|V_1|} = \cfrac{\sqrt{1+(\omega RC)^2}}{\sqrt{4 + (\omega RC)^2}}## I have to calculate half power frequency for both...

Hello, I'm currently working on a problem involving the calculation of an unknown voltage source of a circuit containing a resistor, inductor and load in series. Unfortunately, the problem sheet does not give an answer at the end, so I am unsure as to whether my approach is correct -- hence...

Homework Statement The circuit in operates at 60 Hz with Emax = 170 V, and R = 4.5Ω . How much energy is dissipated in the resistor in 0.75 s? Homework Equations P = VI For a circuit like mine with only a power source and resistor, the current and voltage are in phase, so V = E max sin (ωt)...

Homework Statement How large an inductance should be connected in series with a 120 volt (rms), 60 watt light bulb if it is to operate normally when the combination is connected across a 240 volt, 60 Hz line? (First determine the inductive reactance required. You may neglect the resistance of...

Homework Statement 2. Homework Equations [/B] I am trying to prove the equation $$ \frac{\bar{P}}{V}=\frac{1}{2}E_0^2\sigma_{AC} $$ which can be rewritten as $$ \begin{align} \frac{\bar{P}}{V} &= \frac{1}{2}E_0^2\sigma_{AC}\\ &=\frac{1}{2}E_0^2\ \omega\ \epsilon_0\ \epsilon^{''}_r\\...

Hi. I'm joining this forum to ask about some equipment I need. At the community college where I teach, we do a lab in freshman physics where students measure the input to and output from a transformer. My AC sources are reaching the end of their lives, so I'm looking for replacements. As far...

Homework Statement Homework Equations KVL at that loop The Attempt at a Solution I can easily solve all the individual current and voltages in this circuit using Mesh analysis and Gaussian Elimination. But how do I get Vx? I can simply add the voltages of the two 10uF capacitors if they are...

Homework Statement Need to find Voltage V. I know that I need to first solve for the currents, have tried using loop rules, not having much luck. Homework Equations Just would like to know how to approach, and solve, this problem. ME and circuits has never been my friend, thanks! The...

Homework Statement The circuit above has a 29 resistor and a 11.1 mH inductor. Calculate the theoretical phase difference between the current CPA and voltage VPB if the circuit is driven by a sinusoidal voltage source with a peak amplitude of 3.5 V at the following frequencies: 20 Hz 420 Hz...

I have only just found out about inductors, and am trying to figure out how a circuit with an inductor and a capacitor could change dc current to ac current. With the set up of the circuit, would it suffice just to have the dc supply with a 'gate' that stops/allows through the dc current with a...

Homework Statement [/B] Parallel circuit consists of 100ohm resistor with 0.4A current, a 0.47uf capacitor with 0.177A current. Both connected across an AC supply, determineHomework Equations [/B] The supply voltage The supply frequency Current drawn from supply Power factor of the circuit The...

Homework Statement Determine, using the values given in TABLE A, the current I in the circuit of FIGURE 2 by: (a) mesh analysis (b) nodal analysis. Any help verify for part (a)? And to help me get started with (b) as V3 is driving me nuts. Homework EquationsThe Attempt at a Solution For (a)...

Homework Statement http://i.imgur.com/HTGycr8.png?1 f = 248 Hz\Rightarrow \omega = 1558.23r/s\\ L = 34 mH\\R = 7\Omega\\\alpha = -6°\\C=? Alpha is the angle between current and voltage (V - I). X_L=\omega\times L=1558.23 * 34 * 10^-3 = 52.9798 \Omega Homework Equations \arctan{\frac{R}{X}} =...

Homework Statement A voltage source given by ##v_s(t)=25cos(2\pi\times10^3t-30^\circ)## is connected to a series RC load. If R = 1MOhm and C = 200pF, obtain an expression for ##v_c(t)##, the voltage across the capacitor. Answer known to be: ##v_c(t)=15.57cos(2\pi\times10^3t-81.5^\circ)##...

Homework Statement A series RL circuit is connected to a 110-V ac source. If the voltage across the resistor is 85 V, find the voltage across the inductor. Homework Equations V = IR The Attempt at a Solution How does one go about solving this? My intuition tells me that KVL must be...

Hello, this is not a homework question, but is a past year exam question which I'm stumped at. Any help will be appreciated. 1. Homework Statement We're designing a current reduction system for an AC motor which is modeled as an inductor ##L##in series with a resistor ##R##. This motor is...

Homework Statement In each of the four circuits shown, an AC input voltage, ##V_0 cos(\omega t)## is applied on the left and the output voltage is measured on the right. Treat the input frequency as a...

I have trouble solving the following problem. Am I supposed to start by doing nodal analysis on the loop on the right. Can someone give me a start. Thanks...

Homework Statement An AC voltmeter connected to the nodes A and B shows the same value as when connected to the nodes A and D (refer to attachment). What is the inductance of the inductor? What value does the voltmeter show? The inductor is ideal. U = 70sin(314t) V, C = 80 μF, R = 500 Ω...

Homework Statement An inductance is connected across an AC current generator. Homework Equations v= L di/dt = Vsinωt The Attempt at a Solution i=∫di= V/L ∫sinωt dt= -V/ωL cosωt This is what is written in my book. But wouldn't there be a constant at the end of the indefinite...

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...

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°)...

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...

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...

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...

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 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...