Questions tagged [impedance]
Impedance defines the voltage/current characteristic of any dipole circuit.
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I need help understanding the total impedance in a delta connection
I'm trying to upskill by teaching myself electrical engineering. I already have a degree in theoretical physics and pure mathematics so I don't mind math-heavy answers. While I don't find the maths ...
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Amorphous Silica Electrical Impedance Tomography
I would like to see if the idea I have for an experiment is even worth the effort and money to perform. I would like to use electrical impedance tomography to image a developed thin layer ...
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How important really is the impedance of an USB 2.0 signal line?
The USB 2.0 specs requires a differential impedance of 90 Ohms and a common mode impedance of 30 Ohms (with some tolerance). This, by definition, gives a target of an odd mode impedance of 45 Ohms and ...
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Electrical circuits homework
I am pretty new to circuits analysis and I have the following problem as homework:
ig2(t) = 4sin(ωt + π/4),
e3(t) = 12sin(ωt + π/4),
R1 = 10 Ω,
ωL1 = 4 Ω,
ωL3 = 3 Ω,
1/(ωC2) = 6 Ω
I have to calculate ...
user256787
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Are there measured values for the resistance contribution of vias of different diameters and depths?
I'm interested to know if there are real-world measurement values available for the resistance contribution of vias (or plated through holes).
Sure - there is no widespread definition of what a ...
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Output impedance of a series shunt feedback amplifier
I am trying to find the output impedance of a series shunt feedback amplifier by converting it to a two port network.
I know the input impedance:
Ri=ri*(1+A.β)
But I dont know how I should find ...
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How do I convert S-parameters for impedance matching?
How do I derive the Z-parameters to calculate a matching network for a device? I'm not sure what terms to even search for as I get all sorts of information I am not familiar with.
My task is to ...
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Connect speaker directly to Samsung Galaxy S6. Minimum impedance accepted
I want to connect an external (passive) speaker (3W/16 ohm) directly to my Samsung Galaxy S6 using the headphone jack. I want to do this on my bicycle using the smallest space possible. Connecting the ...
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Two-Way Speakers & First Order Butterworth Crossover
I live in the Upper Hunter of NSW and my knowledge of electronics is rudimentary.
Recently I found a pair of two way bookshelf speakers. The cabinet of both speakers had been opened up and the wires ...
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How to calculate the output impedance of an oscillator?
Is it possible to approximately calculate the output impedance of an oscillator if the rise/fall times at a given load capacitance are known, simply by using the formula for the RC time constant T = R ...
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Small signal output impedance for a circuit with bipolar transistor?
For the following circuit, I need to find the small-signal impedance looking into the collector of the transistor at terminal X, not taking the load resistance Z into account:
My attempt at a SSM is:
...
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How would you design a power divider with 50-Ohm unbalanced input and 4x 100-Ohm balanced output impedances to send RF down a CAT6 cable?
A CAT6 cable has 4 balanced pairs, each at 100 Ohm. I'm wondering if I can make a 50-Ohm coax unbalanced input and split the power to 4x 100-Ohm balanced output (and then merge it back together the ...
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Why the capacitive divider in this output stage?
I have this output driving stage, reverse engineered from a generic Chinese mist generator:
The goal is to drive the piezo transducer with a given frequency (more or less 1.7MHz or 2.4MHz depending ...
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Common term for Resistance and Conductance?
Simple question; Impedance and Admittance are complementary quantities, and can be described by the common term "Immittance". Likewise Resistance and Conductance are complimentary quantities,...
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Circuit Analysis: Difficulty in obtaining a current through a resistor?
I'm solving a problem that requires I compute some impedances, and then the current through a resistor. I obtained some of the impedances*, but don't know how to get the second part (current).
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Twisted pair with shield and drain wire
Ive been posed with a problem regarding calculating the characteristic impedance of a shielded twisted pair with a drain wire. While I understand how to calculate this for a "normal" shielded twisted ...
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How does at low power factor impedance (p.f=R/Z) (if R is constant ) increases while current also increases?
Impedance is equivalent resistance of circuit having resistive and reactive components so if we keep R constant and increase inductance than Z will increase and power factor will going to decrease as ...
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Admittance, Conductance, Susceptance definition
Admittance is the reciprocal of impedance. But:
1) Susceptance is the reciprocal of reactance, or the imaginary part of admittance ?
2) Conductance is the reciprocal of resistance, or the real part ...
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Calculating the off impedance of a relay output by a multimeter
I'm trying to calculate the output OFF impedance i.e. the impedance caused by its RC snubber of this SSR.
So I perform the following test:
Zc is the relay's OFF impedance and Zv is the fluke 114 ...
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Parallel transmission lines impedance
I just want to know the correct way to calculate \$Z_{in}\$ in this network. It's very simple but I think I might be doing something wrong. Is it ok to calculate the impedance over one line and get \$...
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Equations governing the impedance of a generalised constant-phase element in the time domain?
I apologize in advance for the large wall of text, but I feel like to properly ask this question, some background information is in order. I've been recently working on modelling the impedance of a ...
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Bus interface for short distances, many device data exchange - CAN, RS485? + characteristic impedance and media capacitance
I ran into some troubles trying to design a wired bus which will connect in about 64 testing devices. My first choice of mind was CAN bus, known of it's reliability and low EMC interference. However, ...
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How do I perform an electrochemical impedance spectroscopy test for battery?
I have tried to look online for procedures to perform this test but couldn’t find anything. So if anyone can refer me to a set of procedures or give me procedures that I can use to perform the test ...
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Understanding amplitude-time peaks in one dimensional reflection and transmission of sound waves
There is a one dimensional system of interfaces with a transducer sending and receiving sound wave (Plane wave) normal to the interface boundary. The system consists of two mediums, medium 1 & ...
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How to convert Thévenin equivalent to Norton equivalent in this schematic?
I am learning the bus admittance matrix from Power System Analysis by Hadi Saadat electrical engineering. I have a very big problem in chapter 6.2 - Bus Admittance Matrix.
At the beginning of chapter ...
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Finding an analytical expression for a current distribution for conductors in parallel
Recently, I tried to set up an experiment at home to study what path the current takes at different frequencies for the circuit below. I think this will be a fun project, but I'll need your help.
I ...
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RF design_output impedance of the SX1280 LoRa transceiver
I searched the datasheet of the Semtech SX1280, but I can't find the output impedance of the SX1280 (RFIO's pin). Where can I find it?
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Impedance matching 133 MHz - Topology and terminating resistor concerns
I am using the QSPI bus of the RP2040 to talk to a flash chip. I am also putting 8 more chips (PSRAMs) on that bus in my design, and a second RP2040 to load them. The datasheet for the RP2040 isn't ...
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Angle of impedance derivation
I've been working to understand this proof, but some parts are too hard mathematically.
I understand most of it but these two parts. I can't seem to understand. Could someone please help me on this?
[...
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How can I find the output impedance of this circuit?
This is one of the tasks in my BJT amplifier lab. I have to find impedance seen to the right from V1 which can easily be done by taking a frequency sweep and measuring \$\small \frac{V_1}{I_{C_2}}\$ ...
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How do I measure impedance at high power?
I need to measure the impedance of a passive device at its operating power, about 100-watts, and its operating frequency, from 0.1-MHz to 10-MHz. The venerable "operating impedance bridge" ...
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How do you "calibrate" (?) a matching network to re-optimize an S11 match based on physical measurements from a VNA?
We made EDA simulations to match an LNA input and had good results on the simulation (including EM simulation!) --- but when we built the board in real life the S11 match went from -30dB to -7dB. Ouch....
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Is there a way to sense the characteristic impedance of a transmission line?
Is there a way to sense the characteristic impedance of a transmission line?
If a transmission line between a driver and a receiver is 50ohm, is it possible to design a circuit at the receiver end to ...
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Designing of a ribbon microphone (sort of) output transformer
I'm currently working on an experimental string musical instrument. It isn't my invention though. The source of inspiration called Dvina has an unusual pickup system. It senses the current induced in ...
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nature of the load connected to the electric power grid
I know that loads can be modeled either as constant impedance or as fixed power P and Q. I also know that the majority of the loads are constant impedance type but I don't know exactly the percentage. ...
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Why is the relation between voltage ratio and frequency a linear one in a lumped transition line?
In an experiment the cutoff frequency of a lumped transmission line is determined by measuring the ratio of the output/input voltages.
The lumped transmission line is a ladder network of 40 capacitors ...
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Impedance matching method in multilevel inverter
I want to use a five-level inverter as an excitation source for magnetostrictive detection,which should be able to output a 100kHz sinwave. I learned that only if the output impendence of the source ...
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How to calculate the Impedance of a Shielded Differential Connector
I am working on a project involved with a shielded differential connector ,the connector interface as shown,and my question are:
Is there any formula to calculate the impedance ?there is a formula ...
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How to match Transformer output Impedance for Ultrasonic Cleaning Transducer
I have a transformer outputting the 240VAC 40kHz. The Transducer is 50W, 4100pF, 10-20 Ohm at resonance, ~40kHz resonance)
The Secondary of the transformer is 12mH.
I am trying to match the impedance ...
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Power consumption on LPDDR4 command bus - impedance options
I'm trying to solicit and opinion on the use of the 60 ohm transmitter/transmission line/ODT for the command bus of an LPDDR4 bus would be better than 40 ohm target impedance. The system uses an ...
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Is it beneficial to use a taper for the feed input of a PCB antenna?
What is your opinion on using a taper for the feed input of a PCB antenna? Say the feed is 2mm wide and the transmission line is 0.45 mm. Would a taper just cause more impedance mismatch? Or would it ...
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RF via impedance calculation with NFP removal
I'm trying to match the impedance of a RF via from bottom layer to top layer in a 6-layer PCB design. GNSS signal. Unused pad (NFP) removal activated.
The selected via size is 0.9mm pad and 0.5mm ...
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Xilinx FPGA and DDR3 Memory. Confusing Impedance combinations
Currently I'm planning on doing a PCB with DDR3 memory and an Artix7 FPGA. During my research a few questions accumulated.
When looking at the reference manual of the Arty7 board, I see that I have to ...
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Source impedance consideration for ADC
I recently used an accelerometer (ADXL335) in my academic project. This sensor has an analog output.
I interfaced this sensor with a microcontroller (PIC18F458) using an ADC module. It was ...
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How to continuously vary inductance in the range \$[-A, A]\$, A>0?
I require an inductor whose inductance varies continuously as a function of some parameter \$p\$, like a bias voltage or something else that is easily user-controllable (not frequency as I require it ...
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Controlled impedance traces necessary between line driver and series termination resistor?
I'm designing a line driver circuit with the SN74BCT25244 chip. The chip has a rise time of ~10 ns into an open circuit based on my own scope testing, but we are only wanting to drive the signal at a ...
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Emulate impedance response using RLC components
I need to emulate measured impedance response of some blackbox using only RLC components. Measurements:
...
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Finding the total impedance and voltage across open terminals
The question that I'm trying to solve is the following:
In the circuit shown below, what is the total impedance in ohms across the open terminals? What is \$v_{T}\$ if \$v_{L}\$ is 80 vrms?
This is ...
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Two port networks - Why are shared Z-parameters not negative?
In basic electronics we learned that to solve a circuit using mesh analysis, the shared impedances had to be negative. For example in the circuit bellow, the system of equations would be:
$$\begin{...
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Impedance and resonance frequency of a bias tee
I am a beginner trying to learn about combining impedances and solving for the resonance frequency. I am solving a circuit:
simulate this circuit – Schematic created using CircuitLab
and I ...
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