Impedance Definition and 488 Threads

I have this curcuit. I want to discover the output impedance. Using h-parameter model I get the second circuit. I know that Zout= V(open circuit)/I(short circuit) and ie = C ib, where C is an appropriate proportionality factor. Vol = V1 Re/(Rb+Re) = (Rb ib + Re ie) Re/(Rb+Re) Isc = ie = C ib...

I've attached my work below. The numbers seem odd to me though. Are my equations correct? Is the phase angle really (0/12)? If so, what are the implications of that?

I still did not understand this from my previous threads, what is the way to determine the instantaneous voltage across the cavity plates at any given moment, in a klystron I suppose the voltage would be proportional to the arriving electron bunch density which would determine the overall bunch...

Could I get a conceptual answer, supported by math, explaining why coax has less characteristic impedance than open wire feeds?I’m new to EE. Thanks for you patience.

I've been given the following circuit and have been asked to find the input impedance and the impedance between the input terminal and ground. I've never encountered an operational amplifier configured like this. I know that the voltages at the - and + terminals of the op amp are ideally equal...

Homework Statement 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...

I don't fully understand how to work out the impedance from the given equation (5j-5)x(11j-11)/(5j-5)+(11j-11). Any help would be greatly appreciated. Thanks. The answer needs to be in rectangular and polar form.

Good morning, I was reviewing a problem in my book regarding Impedance. I have a question. For the impedance -Z they got 20 ∠53.1° degrees How did they go from 12 + j16 to 20 ∠53.1°. Thanks

Given a sinusoidal voltage source attached to a load, like the following, I want to get both the resistive ## R_o ## and the reactive ## X_o ## components of the output impedance ## R + jX_o ##. Measuring the open circuit voltage will give ##V##. If I connect a test resistance ##R_1## at the...

Hi, The origin of this question was contemplating how to express the impedance of an inductor as a function of frequency, for non sinusoidal voltage wave-forms such as triangle waves, but in particular rectangular pulse trains. So going back to basics, I watched this video: He derives the...

Do we have reflection when the intrinsic impedance η=E/H between two media are matched but not necessarily the characteristic impedance (assuming a transmission line)? Basically, I have a case here shown below I have two parts with different geometries (this may not be a transmission-line, if...

Hi, What's the intrinsic impedance of a resistor? The intrinsic impedance defined as η=E/H ratio of Electric field to Magnetic field? Is it the same as the resistance 'R'? Does it depend on μ,ε of the resistor material or free-space? Also, do we have any electric field surrounding a current...

Homework Statement For one of my assignments I’ve been ask about the relationship between percent impedance and per unit impedance. Homework EquationsThe Attempt at a Solution I know that the x% is determined in transformers by short circuiting the secondary windings and slowly increasing the...

Homework Statement (From Razavi's Design of Analog CMOS Integrated Circuits - Chapter 6) Homework EquationsThe Attempt at a Solution Not too sure about calculating the input impedance of this. Initially I thought that it would be the series combination of C1 and C2, since we are...

These are typical metal roof in my country.. it's connected to iron c-purlins metal screwed to metal sheets. Our structural plans never have any grounding details of this. I'm just wondering what would happen if a live wire touch it or the I-beam connected to it (because we hang electrical wires...

Homework Statement [/B] Given the relationships: ##X pu =\frac{\text{MVA base}}{\text{MVA fault}}## ##=\frac{\text{MVA base}}{\text{MVA rated}}\frac{\text{X%}}{100}## ##\text{fault MVA}=\sqrt{3}\text{VIfault}## ##X\Omega=\frac{V}{\sqrt{3}}I fault## Show that: - (a)...

Homework Statement For the system shown in FIGURE 2, using a 10 MVA base, calculate the fault MVA levels through each unit and the base "voltage" MVA across each unit for a fault at F. Draw the impedance diagrams showing the fault levels and the base "voltage" MVA across each unit for: (a) bus...

I am just a bit confused as to how impedance is matched with RF connectors such as type-N or BNC connectors. I know Coaxial cabling and RF connectors come in common impedance ratings like 50 or 75 ohm but how is this all matched properly? For example many people have told me that when using...

I've been trying to understand how dilution refrigerators work and inbetween intermediate steps, between different temperature points, I see capillaries here and there under the name of impedances. After some googling, I somewhat convinced myself that it's to build up pressure before and after...

Hi all, I am currently working on a project where the output/load consists of both a variable inductance and variable resistance, whilst the circuit driving this load is a class E radio frequency (RF) power amplifier with low resistance but relatively high/medium reactance (attempting to design...

I am interested to know what is the impact of various length scales of impedance changes on wave propagation. From undergraduate physics (a few years ago for me) I roughly remember how to derive reflection and transmission coefficients for a wave traveling from one medium to another with a...

Hi, Say there was a situation in which two strings are joined together, each with respective impedances Z1 and Z2, held under a tension T. I was wondering about the functional dependence of the impedance on the diameter of the strings. Thanks

Homework Statement My electronics&physics lecture notes contain the following side note: ___ "A ladder transmission line comprises an alternating sequence of segments of two different transmission lines both of length $l$ with characteristic impedance $Z1$ and $Z2$. If the line is constructed...

Homework Statement 2. The attempt at a solution Am I doing something wrong? I know it's just voltage division with AC phasors and we have to equate the real parts and imaginary parts to find the unknown, but I feel like the question shouldn't be this hard.

Thank you for reading my post. I was watching the video this video on transformers and saw an amazing demo: From 4:00-5:20 the guy does an experiment where he has a simple transformer circuit set up: On the primary side of the transformer he has an AC power supply, and a lightbulb. On the...

When sound hits a wall,part of it gets reflected and part of it gets transmitted due to acoustic impedance difference between solid and air. My problem,and point of this question is that having material or gas impedance number is completely useless unless we know the frequency and wall...

Hello, I'm having the damnedest time wrapping my head around a concept of audio electronics: http://whirlwindusa.com/support/tech-articles/high-and-low-impedance-signals/ How exactly does a higher impedance bring down the frequency at which capacitance dominates? My current understanding is...

i'm trying to research what might be the difference in two electrical scenarios scenario same in both scenarios- we have a 18"tall x 4"deep x 8" wide carbon steel box, this is mounted to a building and electrically bonded to the electrical system throughout the building and most of the rest of...

Hey everyone, I'm trying to measure the stray capacitance in a circuit comprised of an rf signal generator, an oscilloscope, a coaxial cable (short-circuited) and some capacitors. I measured the resonant frequencies of the coaxil cable for varying values of capacity (0pF to 850pF) between 4MHz...

Acoustic impedance of material is defined by density multiply by the velocity of waves within the base material. My question is if i have a tubular or hollow part with a base material, does this count as a reduction of density compared to the base material of the tube or hollow part. Would the...

Homework Statement Say you connect Circuit A with low output impedance to circuit B with high input impedance. Why does this cause minimal voltage drop compared to connecting them the other way around (high output to low input). Homework Equations P = V^2/R P = IV The Attempt at a Solution I...

I have a question for the community. I am doing a further study and trying to locate any information regarding input impedance of an off center fed dipole at different heights above ground. A simple dipole targets 73.1 ohms for 1 wave length or higher above ground. I am not sure if the same...

Homework Statement Just problem 19C. Homework Equations P=IV=Ieiwt*Veiwt. T The Attempt at a Solution P = IVe2iwt=IVcos(2wt). What did I do wrong?

If a self oscillating electrical (passive) system is excited at two nodes A and B by a sinusoidal current, and if this system has one degree of freedom, then the response of the system is maximal at the resonance frequency. Quantitatively, this means that the ratio of the exciting complex...

All transmission lines have a characteristic impedance which is different based on their length and voltage and frequency (for AC lines) , Also all transformers and their primaries have a different impedance based on the turnsratio, core steel type etc factors. Now I read that for any given line...

Hello, I would like to ask if I have this data from impedance spectroscopy: frequency, Z(im), Z(Real), how should I calculate conductivity ? Should I use R(im) or R(re)?

Homework Statement Find the complex parallel impedance of a 20 Ω resistor and 110 mH inductor from a 50 Hz supply. Homework Equations Z = R (XL2 / R2+XL2) + j XL (R2 / XL2 + R2) The Attempt at a Solution [/B] R = 20 Ω XL = j34.6 Ω Z = 20 ( j34.62 / j34.62 + 202) + j34.6 ( 202 / j34.62 +...

I have to investigate electrical impedance to make progress on a project. Does anyone know of any good resources to begin to understand impedance and reactance, particularly relating to circuits containing inductors and capacitors? I am trying to investigate impedance responses of these circuits...

Homework Statement Homework Equations ##V = ZI## ##Z_R = R## ##Z_C = -\frac{j}{\omega C}## ##Z = \sqrt{R^2 + (\frac{1}{\omega C})^2}## ##P_{av} = \frac{1}{2}V_m I_m cos(\phi)## ##\phi = arctan(\frac{-1/\omega C}{R})## ##\Delta \phi = \phi _1 -\phi _2## The Attempt at a Solution I've found...

Hi All, what is the reason why very close to an electromagnetic source (Fresnel Region), the wave impedance Z0 in free space for electric field and magnetic field is not the same? Z0 for magnetic field increases and for electric field decreases by increasing the distance from the source...

[FONT=Georgia]Dear all, is there anyone with plasma background? I am developing an algorithm for a plasma impedance L type matching network. Initially, I set the Load and Tune units to some specific positions. The algorithm is simply tuning a possible minimum SWR starting from the...

I'm having some problems understanding why my computation deviates from solutions. I thank in advance to anyone who can give me some tips where I've gone wrong. Homework Statement Compute real power on resistors ## R_1 ## and ## R_2 ## and reactive power on inductor ## L ##. Circuit is powered...

Hello, I'm trying to get some feedback on my circuit design (picture below). I am attempting to use a differential op amp to impedance match a 100 ohm transmission line. The transmission line is CAT6A twisted pair. I'm using CAT6A as a feed through into a vacuum chamber. The design is to...

I am trying to determine the primary magnetizing inductance + core shunt resistance of a transformer. I attached the equivalent circuit of the transformer. I left the secondary open and have an AC voltage on the primary. This causes the coupling leakage inductance and coil resistance to appear...

Hello. Resistive Ohm's law is famously known as V = IR. We can derive its microscopic version as being followed. V = El, where E and l are, respectively, an electric field and a resistive load length over which a voltage drop V is developed. I = JS, J and S are a current density and a...

To measure negative sequence impedance of an alternator, we short the white and blue phases, measure the current and then divide it by the voltage of the red phase. Then to measure zero sequence impedance, we short the rotor and connect the stator in open delta and inject a current. My...

Homework Statement A 25-Ω antenna is connected to a 75-Ω lossless transmission line. Reflections back toward the generator can be eliminated by placing a shunt reactance Z at a distance l from the load (Fig. 1). Determine the values of Z and l. Homework Equations...

Homework Statement [/B] a ##50\Omega## lossless transmission line of length ##0.4\lambda## is terminated in a load of ##(40+j30)\Omega##. Determine, using ##Zin=Z0\frac{ZL cos \beta l+j Z0 sin \beta l}{Z0 cos \beta l +j ZL sin \beta l}## the input impedance to the line. ##Z0=50\Omega##...

Hello. Please looks at the attached image first. The left image is LCC impedance matching network (one of T-type impedance matching networks) and the right is the corresponding equivalent circuit when CT and CL are adjusted such that an equivalent impedance of the sub-circuit surrounded by...

Hello. Please look at the attached image first. There are two circuits A and B which have individual electrical components a and b. Components a and b are electrically and directly connected by the red lines. Impedances of individual components a and b are not matched, however, equivalent...