What is Ac circuits: Definition and 75 Discussions
In circuit complexity, AC is a complexity class hierarchy. Each class, ACi, consists of the languages recognized by Boolean circuits with depth
O
(
log
i
n
)
{\displaystyle O(\log ^{i}n)}
and a polynomial number of unlimited fan-in AND and OR gates.
The name "AC" was chosen by analogy to NC, with the "A" in the name standing for "alternating" and referring both to the alternation between the AND and OR gates in the circuits and to alternating Turing machines.The smallest AC class is AC0, consisting of constant-depth unlimited fan-in circuits.
The total hierarchy of AC classes is defined as
So I've seen other threads on here with the same problem from a few years ago, and I'm just not getting the same answers. However, I followed along with a similar problem in the textbook and used all the same methods, so can't understand where I've gone wrong, or if I even am wrong. Also not...
We are tasked to solve for the steady state voltage v using superposition theorem. I start with solving with voltage source using mesh analysis and got the current flowing through the 3 ohms resistor and get the first value of the voltage which is 3.2cos(6t+126.87). Now my problem is I am...
Specifically for part (i) and (ii), I get the rough idea that when the voltage of the AC source is decreasing, the capacitor can discharge to "cushion" the drop in voltage. However, I have some questions about when this occurs.
1. There is an assumption that the capacitor will be charged to...
The problem is shown below: (I am only asking about part b)
^Above is the problem.
Below is the solution to part b. They have claimed that we can set potential at C = D = u(t), and A=B=0. Why is this claim true?
What I realize:
By applying Kirchoff's across ACDB, Voltage across C1 = Voltage...
where: 𝑣𝑖𝑛(𝑡)=0.3𝑐𝑜𝑠100𝑡
I have read all over the internet that this differential equation can be solved by isolating the term with the highest degree on one side of the equation. After doing so, I integrated it. However after integrating, I don't know that the next step is. Can anyone help me...
I am doing an experiment in electronics with AC RLC circuits, But there are a few things about what I need to do that I don't understand.
First: While I know in the circuit diagram we include the internal resistance of the Inductor in series, but I don't know why we include it in series rather...
The first picture is a regular ac circuit, where the voltage alternates between 240V/0V in one of the wire. The second picture is a live/hot & neutral ac circuit. Are these 2 different type of circuits? And if I connect the top circuit to the ground which makes it neutral (just like the pic in...
Homework Statement
similarities and differences of AC and DC current in simple circuits. Outline using diagrams and a clear desciption the loss of energy in DC circuits and power loss reduction of AC when transmitted.
Homework Equations
N/A
The Attempt at a Solution
DC loses energy over long...
Homework Statement
For a series LCR circuit,the voltage across the resistance,capacitance and inductance is 10V each.If the capacitance is short circuited,the voltage across the inductance will be
(a)10V
(b)10/√2V
(c) 10/3v
(d)20V
Homework Equations
Potential difference across...
Homework Statement
The output voltage, V_(out) (t) ‡ q(t) /C, effectively measures the charge on the capacitor as a function of time, where q(t) is an exponentially damped simple-harmonic oscillation:
a) Given that L = 0.05 mH, the square-wave frequency is 25kHz, and the ringing decays to 40%...
I'm having trouble understanding RLC circuits. If I have a resistor, capacitor, and inductor connected in series and I'm GIVEN the current through the resistor, How do I find the currents through each component? Is it the current that was given for the resistor (since they're in series), or do I...
Homework Statement
A capacitor is made of two parallel plates of area A, separation d. It is being charged by an AC source. Show that the displacement current inside the capacitor is the same as the conduction current.
Homework Equations
Idisp = ε(dΦE/dt)
Q = CV
C = Aε/d
Xc = 1/(2πƒC)
Q(t)...
I know that when you get a current from a voltage (like calculating current through resistor), the current and voltage equations have the same frequency. Does this still hold for power P = VI ?
So assume V in Euler form, V(t) = Vcos(wt+theta) + jVsin(wt+theta) = V*ej(wt+theta) and in Phasor...
Homework Statement
Prove that current ##I = I_0\sin{\omega t}## can be rewritten as ##I = I_0 e^{i\omega t}##
Homework Equations
Euler's formula ##re^{i\theta} = r(\cos{\theta}+i\sin{\theta})##
The Attempt at a Solution
If ##r = I_0## and ##\theta = \omega t ## then ##re^{i\theta} =...
Homework Statement
Homework Equations
##a + bi## complex notation
Rules of resistors given in part b
b = imaginary part
The Attempt at a Solution
For part (a) how do I rewrite I(t) as a + bi?
For part (b) I need a formula that equates Z to R.
For part (c) do I simply write b (from part...
Homework Statement
Please see attached image 1 and image 2
Homework EquationsThe Attempt at a Solution
Alright so I believe I solved part a correctly. It was very easy.
(A) 5 * phasor of 30 degrees
However it's been a while since I took circuits 1, so I'm struggling a bit with part (b)...
Homework Statement
Hello everyone, I have recently come under some stress from not being able to get these answers correct. I need to calculate these values:
Zeq
IT
XL2
XL1
VR1
VR2
VL1
VL2
For this series circuit:
And these values:
Zeq
IT
XL2
XL1
IR1
IR2
IL1
IL2
For this parallel circuit...
Homework Statement
It can be shown that a square wave can be represented by a sum of sine waves as given by the formula below
v = v0sinωot + v1sinω1t + v2sinω2t + v3sinω3t +...
Solar cells have an output that is dc. The pd across a cell depends on the incident radiation and the efficiency of...
Homework Statement
For the balanced three-phase loads shown in FIGURE 3,
ZY = (15 + j15) Ω and ZΔ = (45 + j45) Ω. Determine:
Uploaded file C1.png
(a) the equivalent single Δ-connected load,
(b) the equivalent single Y-connected load obtained from the Δ-Y transformation of (a) above,
(c) the...
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...
Homework Statement
In the circuit shown in Figure Q2(b), two loads A and B are connected to the source. The cable connecting the power supply to the load is modeled as series R and L of values R = 0.1Ω, L = 0.1 mH as shown in the figure.
The loads have the following specifications...
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
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...
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...
When doing calculations on AC circuits, what is in your opinion the best notation? Here they mostly use complex notation. For example: V(t) = Vmaxeiωt. In US textbooks (at the non-EE level), they only use ordinary notation. Example: V(t) = Vmaxcos(ωt).
I have a feeling that complex notation is...
Let's say you have a sine wave V=2sin(2t) V. For this peak to peak voltage is 4V.
Then let's say that everything below V=0 is cut off.
Is the peak to peak value for this just from 0 to 2V? Making Vpp=2V?
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...
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 ...
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!
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.
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??
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...
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'm working on an ac circuit, and we were told to use nodal analysis. Furthermore, we are asked to show a power balance between the sources and the power dissipated in the resistors, along with a reactive power balance between the sources and the inductors and capacitors.
I have this formula...
For the circuit given in the power factor is 0.72 lagging and
the power dissipated is 375 W.
Determine the:
(1) apparent power
(2) reactive power
(3) the magnitude of the current flowing in the circuit
(4) the value of the impedance Z and state whether circuit is inductive or...
Homework Statement
A complex AC voltage is given by the equation
v = 3e^j450t :
Note the use of bold v to represent the complex voltage.
For this voltage waveform, what are the values of
-volltage amplitide
-frequency
-instantaneous voltage
-graph it in a argand diagram at t=pi/1800
Homework...
Hey there,
I've been learning about AC circuits recently and while considering and LCR circuit it occurred to me; it's possible for the voltage drop across a capacitor/inductor/both to be greater than the voltage source itself however I can't think of the reason for this, any hints or reasons...
Homework Statement
What is the inductance in a series RL circuit in which R = 7.0 kΩ if the current increases to one half of its final value in 26 µs?
Homework Equations
am i correct in assuming that i should be using the time constant equation: Tau=L/R
The Attempt at a Solution...
Hi, PF :)
I was self-studying AC circuits, and my main goal right now is to understand impedance. However, before that, I was wondering how one would derive the formulas for alternating voltage (and current), namely http://upload.wikimedia.org/math/5/a/0/5a0ecaa1432c6cdce653a943b4962a21.png...
Homework Statement
An AC power supply with a peak volatge output of 200 volts, operating at 60 Hz, is connected to a 53 microFurad capacitor
A) what is the difference in phase angle between the applied voltage and the current
B) what is the rms current in the circuit
C) what is...
im taking circuit theory 2, which is all about ac circuits, but don't have enough money for a book
need a place to learn about how to calculate lead and lag based on the inductance and capacitance, nortons and thevinans and all that stuff but in the context of sinusoidal currents and voltages
Hey guys I just need some help on something
The question is: A motor attached to a 120 V/60 Hz power line draws an 8.50 A current. Its average energy dissipation is 800 W.
I got the first 3 parts of this question correct...
1. What is the power factor
ans = .784
2. What...
Homework Statement
An electric motor draws a 1A (rms) from the 230V (rms) mains. and is found to shift the phase of the 50Hz alternating current by 30% of the period. What is the self inductance of the coils in the motor?
Homework Equations
The Attempt at a Solution
i've started...
Hello,
My prof showed a way of dealing with difficult circuits using complex numbers. But I have no idea what he was on about, and can't find that method in any book.
Does someone know what I'm talking about, and can someone point me in the way of some materials for this?
Thanks!