Impedance Definition and 488 Threads

Homework Statement This question should be quite easy, I'm really struggling though. http://img32.imageshack.us/img32/5241/potdiv.png 1) Write down two simultaneous equations for this circuit that describe the voltage as a function of current 2)Write down the impedance matrix that relates...

Hey. Say you have an RLC circuit with an AC supply. Then I=ei(ωt-α). My question is: will α always exist, ie will the current always be phase-shifted compared to the voltage, as long as the impedance has an imaginary component or if the circuit is not at resonance? Does Z = |Z|*eiα, where α =...

So I am well familiar with how bi-state logic (with 0s and 1s) works in gates. 0+0=0; 0+1=1+0=1+1=1 etc. What happens if an input to a gate is neither 0 nor 1, but has an high-impedance value? Will it disable the logic gate from working? Will the logic gate simply ignore that input? Anyone...

My textbook doesn't cover transformers in very much detail at all, so I only have a very vague idea as to how they work... Homework Statement The secondary voltage of an ignition transformer in a furnace is 13.9 kV. When the primary operates at an rms voltage of 120 V, the primary...

Firstly, there are lots of ways to word the definition of voltage, but the one that intuitively makes the most sense to me is as follows: "One volt is when: The difference in (electrical potential energy per unit charge (q)) between two places equals one." [SIZE="1"]*per unit charge meaning...

I find that the acoustic impedance is given by Z= Pressure/ Velocity I read that the acoustic impedance of a plane propagating wave is given by Z = ρ0c. What is ρ0 and c? Thanks a lot

My Working for part (i); Determine the total impedance Zt: Z1=70+j0 + 0+j50 =70+j50 = 86.023<35.537°Ω 1/Z2=1/-j80 + 1/86.023<35.537° =j0.0125+0.0116<-35.537° My question is do 35.537° need to be divided by 1 like 86.023? If not why?Thanks.

Homework Statement Two resistors, a capacitor, and an inductor are connected as shown. What is the frequency at which the impedance is purely real? Diagram below Homework Equations Inductor: Z = jwL Capacitor: Z = \frac{1}{jwL}=\frac{-j}{wC} Resistor Z = R The Attempt at a...

I would like to impedance match a few joints in a circuit and would appreciate some thoughts about this, since I would like the match to be as perfect as possible. The problem is complicated by the fact that the available equipment only consists of trimpot(s). The joints are mostly cables to...

I'm currently taking a junior circuits lab that expects familiarity with impedance (my intro E/M course never covered it), so I just want to make sure I did these two impedance problems correctly (the second one asks merely for a formula, so no calculation was done): Later in the...

Just wondering here... What is the difference between impedance and resistance? Is resistance typically used to describe the nature of a circuit element, while impedance is of an entire circuit? I have looked up the definitions for both, and I just don't see the difference between them. Thanks!

Hi everyone. I'm doing an experiment where I measure the capacitance of a capacitor. However I want to make sure that the output impedance of the function generator is low (to get accurate results). My circuit is attached. How do I calculate the impedance from the information provided? Help is...

Homework Statement A load absorbs 58959W at a lagging power factor of pf = 0.73. If the current flowing through the load is ix = 0.001A-rms , determine the impedance of the load. Homework Equations Ohms law Impedance/Voltage/Power Triangles The Attempt at a Solution If the load...

Homework Statement Given the equivalent impedance of a circuit can be calculated by the expression Z= (Z_1 Z_2)/(Z_1+ Z_2 ) If Z1 = 4 + j10 and Z2 = 12 – j3, calculate the impedance Z in both rectangular and polar forms. Homework Equations j2=-1 The Attempt at a Solution Z=...

Homework Statement An impedance 8 + j7 Ω is connected in parallel with another impedance of 5 + j6 Ω. this circuit is then connected in series with another impedance, comprising a resistance of 5 Ω in series with a capacitive reactance of 7 Ω. The complete circuit is then connected to 150...

A 1000 ohm resistor, 500 picofarad capacitor, and 2 millihenry inductor are all conducted in parallel. What is the impedance if the frequency is 10 kilocycles per second? 10 megacycles per sec? At what frequency is the absolute value of impedance the greatest? I know I start by considering...

I'm having a really hard time understanding input vs. output impedance and also the usefulness of the Thevenin model. Let's say we have a simple voltage divider consisting of two equal resistors. The output voltage is between the resistors. If the input voltage is 10v the output voltage has...

Homework Statement Problem description: http://imageshack.us/a/img707/2060/beskrivelse.png Homework Equations http://imageshack.us/a/img543/5302/lign1.png Z = Z_1 + Z_2 + ... +Z_n (Series), \frac{1}{Z}= \frac{1}{Z_1} + \frac{1}{Z_2} + ... + \frac{1}{Z_n} (parallel) The...

Homework Statement 5. What is measurement technique in impedance analyzers? 6. Draw the circuit of a two terminal impedance measurement. 7. Draw the circuit of a three terminal impedance measurement. 8. Draw the circuit of a four terminal impedance measurement. 9. How can you calculate...

I'm trying to determine the best method of measuring impedance from a wire through it's glass coating to determine if the thickness of the coating is correct. At the moment I do not have the actual frequency, I just know it is in the RF range and that my impedance needs to be 50 ohms. I've...

OK. I hope this question is acceptable here. I am studying to take my Ham Radio License Technician's Class exam and I am not sure about the topic of load impedance and load in general. I looked up "Load impedance" on wikipedia, I'm confused This sentence "when a high power appliance...

Homework Statement A 29kΩ resistor is in series with a 62mH inductor and an ac source. Calculate the impedance of the circuit if the source frequency is 80Hz . Homework Equations XL = ωL Z = [(R^2 + (XL - XC)^2)] ^ 1/2 The Attempt at a Solution R = 29,000 Ω XL = 0.062 H...

Homework Statement Design a suitable combination of resistors, capacitors, and/or inductors which has an equivalent impedance at ω=100 rad/s of 1Ω using at least one inductor. Homework Equations Zeq=ZR+ZL+ZC ZR=R ZL=jωL ZC=-j/ωC The Attempt at a Solution I really am not sure how to start. I...

Hi there, I am supposed to measure the electrical impedance (which depends on conductivity) of an electrically conducting object by use of eddy current technique induced by an air core coil. for this purpose I need to print a circuit. would you please help me with the characteristics and out...

This is my first time posting so forgive me if I screw it up. I have attempted to attach the file, I hope I have done so correctly. I am trying to solve a series-parallel RLC circuit problem. I have a 220Ω resistor in series with 180Ω resistor, a 1mH inductor and a .47μF capacitor all in...

Homework Statement [Edit: Sorry for the typo in the thread title] I'm doing a problem that involves taking the derivative of the impedance of a parallel RLC circuit with respect to the frequency ω of the applied voltage. I have to then set that derivative equal to zero to find the frequency...

Homework Statement see attached Homework Equations The Attempt at a Solution $$\eqalign{ & {V_1} = {Z_{11}}{I_1} + {Z_{12}}{I_2} \cr & {V_2} = {Z_{22}}{I_2} + {Z_{21}}{I_1} \cr & {\rm{ - - - - - - - - - - - - - - - - - - - - - - - - - - - }}...

(This is not a question I was given to solve, it is a question about the course notes.) Homework Statement In impedance matching, what is the next best method after the complex conjugate method? If the source has V_s and Z_s, what should Z_L be? V_s, Z_s, and Z_L are in series. Homework...

Homework Statement I need to find the total impedance in a circuit that has: j60 ohms, 30 ohms, -j60 ohms and 20 ohms in parallel Homework Equations Ztotal=1/(Z1+ Z2+ Zn) The Attempt at a Solution I've tried doing this, but what I think is the -j60 and the j60 should cancel...

1. I know that 1/2 of the real part of the complex poynting vector gives the average power flow per unit area. But what is the significance of its imaginary part ? 2. What is the significance of the complex intrinsic impedance ? For lossless medium (i.e. with no ohmic losses) it is real , but...

Homework Statement Write code to calculate the input impedance on a thin wire antenna using the below form of Pocklington's integral equation. Use Method of moments. Use a pulse as the basis function, point matching and delta-gap generator as the 'source'. Assume the wire is broken up into 7...

A 10-H inductor, 200-Ω resistor and a capacitor C are in parallel. find C if the magnitude of the impedance is 125Ω at ω=100rad/s Now i attempted to solve it by first doing the parallel combination of the inductor and the resistor. Then i would do the parallel combo of these with the...

In this thread Antiphon had written that When I first encountered that, I thought there's something wrong with that, but could not figure it out. In order to create a current the electron must flow from one place to another. But in EM radiation although the electron oscillates or jiggles, it...

Hi all, I have a number of underwater transducers that I want to measure the impedance of by using an impedance analyzer. I'd like to create an automated system that cycles the leads of the impedance analyzer to the various transducers, perhaps using something like a decoder or a number of...

how could i lower the impedance affecting a certain material. I am sure there is a circuit i can use to do this can anybody help??

I am simulating a series-parallel tank circuit in MATLAB. This means parallel resonance (inductor and capacitor in parallel) with an added capacitor in series. I would assume the resonance condition is w^2LC = 1 and the impedance is 1/(1/(z_L+z_R)+1/z_C1) + z_C2 with C1 being the parallel...

Can anyone help me with impedance matching WITHOUT using smith charts. I am trying to develop a mathcad template to calculate imput impedances for normal power line systems as well as parallel and series impedance matching. I was not very good at using smith charts and never really got the...

Homework Statement Transmission line is designed so it has selfinductance, L = 7.0x10^-7 Hm^-1 & signal speed 70% of c Find characteristic impedance Homework Equations Z = √L0/C0 Ω also v = 1/ √L0C0 The Attempt at a Solution So L = 7.0x10^-7 Hm^-1 v = 0.7c (c = 3x10^8...

I am working on an animal vocalization study and I need a clarification about acoustic impedance. All of the sources I have gone to are a bit too technical for me, so if you would be so kind to answer my question I would be very grateful! My question is this: What happens to a sound in high...

Homework Statement Find the equivalent impedance of the infinite series of resistors and capacitors as shown below [FONT="Courier New"] -R----R----R----R----...R----... ____C____C____C____B_______C -r----r----r----r----...r----... Homework Equations 2.1. Equivalent resistance of resistors in...

I wiki'd it and I am still having some trouble understanding it. Is it basically like resistance for AC circuits? Then why is resistance still mentioned when talking about AC?

Homework Statement I come across the impedance for an inductor an capacitor combined is Z = XL - XC, for a resistor and capacitor in series is Z = sqrt(R^2 + XC^2) and how do you obtain a formula for a combination of a capacitor, an inductor and a resistor in series and in parallel...

Homework Statement 50 volts, 60 Hz http://peecee.dk/upload/view/363429 I have to find the current through R, C, and L. Total current. Totalt impedance. Homework Equations I=(U/Z) The Attempt at a Solution See picture: http://peecee.dk/upload/view/363430 For I_R it must...

Homework Statement Describe how the Earth wire and fuse in an appliance with a metal casing protects the user from shocks if a short occurs to the casing. Homework Equations The Attempt at a Solution I said that the Earth wire provides a low impedance path to ground. As electricity...

Hello, I was trying to derive the transfer function of a simple inverting op amp topology, incorporating the output impedance, Ro, of the non-ideal op amp, to see how it, when combined with a load capacitance can induce oscillations (or at least ringing). I haven't been able to get a valid...

So I've been trying to figure out what I'm doing wrong regarding a theoretical aspect of this lab. I've used both ideal analysis and experimental analysis and can't figure out if I'm doing this right. The circuit is shown produced in Multisim below: The function generator produces a...

Homework Statement I drew the emitted audio amplifier in the picture below. When I looked at my lab manual, it says the impedance should be Zin and Zout, which Zin = R1*R2/(R1+R2) and Zout = Rc I have a few questions about impedance relate to this circuit: 1.) I saw the...

Homework Statement A circuit contains two elements, but it is not known if they are L, R or C. The current in this circuit when connected to a 51.0 V, 60.0 Hz source is 3.60 A and leads the voltage by 75.0 degrees. What is the impedance of this circuit? Homework Equations Z=sqrt(R^2 +...

Help finding the load impedance of a transmission line? How do you find the load impedance of a transmission line?

So we are told in our class that the characteristic impedance of a coaxial cable is impractical to be at a value like 500Ohms. Why is that? The assumption is that the transmission line is lossless and that the dielectic constant (Er) is 1