Calculating Impedance Help!
Homework Statement
calcuate the impedance at the frequency 10Hz of a:
-4.7 kil0 ohm resistor
-1microFarad capacitor
-25mH inductor
Homework Equations
w=2*Pi*f
The Attempt at a Solution
for the capacitor impedance= 1/20*Pi*1*10^-6
for the...
hi
i want to find the output impedance of the following cct so i can perform pi matching on it but i don't know how to find it using lt spice please help!
added schematic
Homework Statement
Consider a circuit, composed of a resistance R and an inductance L in series with an AC generator providing a voltage V(t)=V(subscript 0) cos (omega*t)
calculate the total impedance of the circuit, and the phase difference between its resistive and inductive components...
Let's say we have a circuit composed of simple linear circuit elements (resistors, inductors and capacitors). Now we calculate the Thevenin equivalent circuit for some load within this circuit, and we determine the Thevenin impedance, Z_t.
My question is this: Is it generally the case that...
The question is: "In polar coordinates, what is the impedance of a circuit that has an admittance of 7.09 millisiemens at 45 degrees?"
The official answer is: "141 ohms at an angle of -45 degrees".
I don't understand this. 7.09 millisiemens is 141 ohms, and the positive phase angle...
A slotted line used on a 150ohm lossless transmission line connected to an unknown load impedance, ZL. The voltage standing wave ration is found to be equal to 3. The distance of the first voltage maximum from the load is found to be 9 cm, and the first voltage minimum is located at 3 cm from...
I'm working on a high power multi-phase DC/DC converter where the load current has some fast transients. We can easily measure the output voltage in the time domain, and also measure the power distribution network impedance in the frequency domain.
So, I think I would try converting the...
Homework Statement
I'm trying to determine this insane circuit's |Z| so I can use an AC voltage to find the current as a function of time.
This is my circuit (the switch is closed, and ignore the values): http://i.imgur.com/mA55I.png
Homework Equations
Impedances for each of the RLC...
Homework Statement
A plane wave is passing through a metal. Show that the impedance Z can be given by
Z = \sqrt{ \frac{2 \omega \epsilon _0} {\sigma} } \frac{Z_0}{1-i} where Zo is the impedance of free space and sigma is the conductivity.
You may assume that E is polarised in the x...
Hi, :smile:
Please have a see Example 1-5 on the given link:
http://img854.imageshack.us/img854/8376/inputimpedance.jpg
The example mentions input impedance. What is it in simple words? The book says: Because this input impedance is across the measured terminals , a small current flows...
Okay, so my short experience in radio has taught me that the input and output of every RF system is designed around some certain impedance. Typically 50 ohms or 75 or 300... So you take a transmitter and hook it to a tuned antenna with some sort of feedline like coax.
The coax is the same...
Hi everyone,
I seem to be having a little trouble with parallel impedance. I have the equations, but I don't understand why, I am not asking for a super proof, just an explanation.
So basically we have a circuit of:
ac source, then a capacitor and resistor in parallel.
the formula...
Homework Statement
Homework Equations
V=IR ?
The Attempt at a Solution
My main problem with this question is that impedance seems to apply only when inductors and capacitors are involved, but this circuit includes only resistors, so it seems to me like I could just treat it as resistance...
Homework Statement
Calculate the impedance Zab across ab.
w=0.75 Hz
wo=1 Hz.
L=1 H
R=1 Ohm
C=1 F
Inductor and Capacitor are in series, and together are in parallel with the resistor.
circuit looks like a capital A, but square on top, and rotated 90 degrees clockwise.. if that...
Homework Statement
here is the circuit I am trying to figure out
Homework Equations
I have to find the total impedance for the circuit.
The Attempt at a Solution
I know how to find the total impedance in a series circuit and in a parallel circuit when I have just the Resistor...
Homework Statement
Find the input impedance Z. (i.e. Find Z equivalent.)
Answer in the back of the book: Z=84.907-j20.12 ohms
[PLAIN]http://img834.imageshack.us/img834/8508/circuit.png
Homework Equations
n/a
** j=sqrt(-1)
The Attempt at a Solution
I combined the 60-ohm, 50-ohm, and...
http://img146.imageshack.us/img146/9356/capturexh.jpg
Attempt at Solution:
Well I put R1 and C1 in my RCL circuit, and then used the GIC rules to calculate the "L" inductance for the remainder of the circuit using R2,R3,R4,R5, and C2.
So I did X = (Z1*Z3*Z5)/(Z2*Z4)
where Z1=R2, Z2...
Homework Statement
Calculate the output impedance of the emitter-follower circuit called a pass transistor. Assume that beta=200
**See attached diagram**
Homework Equations
The Attempt at a Solution
Not really sure how this works, I thought it would just be 1k cause that is the...
Assuming very small losses, find a condition relating the mechanical impedances of the supports at the ends of a bar of length L and longitudinal wave speed c if the bar is to have an integral number of wavelengths between its ends when it is vibrating longitudinally.
mechanical impedance...
Hello all,
This question might be at the same time both general and very specific. Admittedly, it has been over 10 years since I really thought about circuit analysis, but I hope I might get some help here! So, thanks in advance!
I will ask a few questions here to make the presentation...
Homework Statement
An emf Vosinwt is applied to a circuit which consists of a self inductance L of negligible resistance in series with a variable capacitor C. The capacitor is shunted by a variable resistance R. Find the value of C for which the amplitude of the current independent of R...
Hi guys,
can anyone tell me the reason why we set Vi=0 (short circuit the input side) when we want to find the output impedance Zo but we don't do the same by setting Vo=0 when we find the input impedance Zi?
and why do we let Io=0 (open circuit the output side) to find the gain Av?
thank you
Homework Statement
Find the specific acoustic impedance for a standing wave p=Psin(kx)exp(jwt) where p is a complex variable.Homework Equations
z = p/u (all variables are complex)
u = (A/rho_sub_0*c)*exp^(wt-kx)The Attempt at a Solution
Approaching this problem it seems that I have all of the...
Homework Statement
I have attached the problem and all my work. If someone can check my work for part a, that would be great. As far as part b, I need the most help here. Finally for part c, I think my work so far is correct, but I need help to graph it. Thank you in advance.
Homework...
Homework Statement
An impedance 1000(1 + i) Ω (and note it contains an imaginary
part) is connected across an AC voltage source of amplitude 10 V
and frequency 60 Hz. Whatʼs the power dissipated during one cycle
within the impedance?
Homework Equations
P = Re(V*I), where V* is complex...
Homework Statement
The circuit is a resistor (200 ohms) and a capacitor (200 nF) in series, and that is in parallel with an inductor.
Homework Equations
[tex]$Z=j \omega L$[\tex]
[Gah, how do I make the latex render?]
The Attempt at a Solution
I'm not really sure where to start with this...
Urgent! About Impedance
the total ohm of this impedance ( 30+j40 ) is 50ohm.
but wat is the conjugate impedance ?? 30-j40? total ohm is wat?
30+j40 is 50ohm
solution is square root of (302+402)
Homework Statement
Question 2 on this paper:
http://www.eng.cam.ac.uk/teaching/past_papers/examples_student/examples_IA/P3_LCD_Q/1ap3lcdq003
Homework Equations
Z = V/I
V=L di/dt
The Attempt at a Solution
for part a of the question:
I began with V = Vo cos(wt)
And I = Io cos (wt + k)
I...
Homework Statement
consider a circuit expressed by v(t)= 100cos \omega t
and i(t)=2cos(\omega t+\pi / 3) .
Find the reactance.Homework Equations
Z=\frac{V}{I} = R+jXThe Attempt at a Solution
Z=\frac{100}{2\angle \pi /3} = 50\angle -\pi /3 = 46 - j19
Does the negative imaginary part mean...
Homework Statement
find total impedance of a circuit with R1 and L in parallel with R2.
circuit looks like this (but with R2 instead of C): http://wpcontent.answcdn.com/wikipedia/en/thumb/7/75/RL_series_C_parallel.svg/160px-RL_series_C_parallel.svg.png
Homework Equations
formula for two...
In my book (Storey), there's an exercise with a parallel RC circuit, where R = 80 Ohm and C = 30 uF. The answer for the complex impedance is supposed to be 40-j40, however I can't seem to get there! I've showed my working under. Am I doing something wrong, or is the book's answer wrong? (freq...
Hello
Am reading about amplifiers, and the articles i read suggests that for a successfull amplification the op amp should have an input impedance and zero output impedance.
I want some explanation about this information, why the input and output impedance are important factors?
Hi,
I'm trying to model the input impedance of a MESFET by using a series RLC circuit.
For example I have the following reflection coefficients:
.575 angle(-138) at 6 GHz
.617 angle(170) at 8 GHz
.610 angle(128) at 10 GHz
As you can see, as the frequency changes so too does the angle. Does...
Hey,
The impedance of the series and parallel RLC circuit both tend to R near the resonant frequency (one is a min/ one is a max) so if I expand the frequency around this point I should be able to show they are the same for \delta \omega small right? For some reason I can't get it to work. Any...
Hi there,
I have a circuit in which consists of a resistance (rs) in series with parallel combination of capacitor and resistance(rc). I want to calculate value of rs. So i did this by calculating total impedance Ztotal which is V/I and then substracting impedance of parallel rc circuit...
Hello,
I wonder if there's any difference between the "impedance matching" and "maximum power transfer" criterion?
I assume in both cases, one impedance should be designed to be the complex conjugate of the other.
Thanks.
Homework Statement
Hi. Just like the title says, why is the output impedance of an op-amp so small?
(as in physically, I understand why a low output impedance is a desirable characteristic)
I need to make an impedance matching circuit using microstrip lines.
Zin --> MATCHING CIRCUIT --> ZL
The input impedance (Zin) is 50Ω. The impedance at the load is 50 - j 500Ω. Design frequency of 900MHz.
The board I am required to use is the Taconic RF-35. It has a thickness of d = 1.524mm...
Homework Statement
Hi!
We have a parallel circuit on 230V, 60Hz voltage. One of the parallel's has a 0.0768H coil, the other has a 50 Ohm resistance on it. The question is: What is the effective I in the main current?
Homework Equations
Z = Lw
The Attempt at a Solution
OK, so I...
Homework Statement
The following three impedances are connected in series across a 100-V, 20-kHz supply:
(1) a 12-Ω resistor, (2) a coil of 100 μH inductance and 5-Ω resistance and (3) a 390-nF
capacitor in series with a 15 Ω resistor. Sketch the circuit diagram, impedance diagram and the...
I'm a bit lost on this one. Also, what formula do I use for impedance?
http://i111.photobucket.com/albums/n149/camarolt4z28/2010-09-19202315.jpg?t=1284947003
http://i111.photobucket.com/albums/n149/camarolt4z28/2010-09-19202817.jpg?t=1284947014
Good Morning
can anyone help explain what this statement really means, when referring to a npn transistor in common mode, as an amplifier.
"The collector is a high impedance when compared to the emitter"
what's the pratical implication of this statement
thanks
David
Homework Statement
A digital voltmeter is used to measure the resistance and voltage of a circuit.
The resistance and voltage measured is used to calculate current flowing.
What errors does the input resistance of the voltmeter introduce into the determination of current?Homework Equations
I...
Homework Statement
In a circuit consisting of a capacitor (Voltage across is 3.2V) and a 47\Omegaresistor (Voltage across is 4.65V), with a current of 0.0989A and a phase difference between the two voltages being 90', what is the complex impedance for the circuit?
Unsure of how to work this...