Impedance defines the voltage/current characteristic of any dipole circuit.

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How to simulate and or calculate complex impedance of LC circuit

Let's say I have a matching network made up of inductors and capacitors like this. How would I go about simulating to get the complex impedance of this circuit at my frequency of interest. Something ...
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1answer
38 views

Function generator output voltage

In a function generator, when I set Zout to be 50 Ohm, and Vpp is 1V. Is this Vsource, or the Vload when I have a matching load of 50 Ohm? simulate this circuit – Schematic created using ...
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32 views

Alternative Gigabit Ethernet Connector - considerations for impedance, signal integrity, and EMC considerations?

I have a design that does not have enough vertical clearance for a standard RJ45 socket. I'm hoping to use a connector like this one from Molex. I will use Cat5e cable when building my cable with the ...
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41 views

Protoboard limitations when dealing with high impedance circuits?

I understand protoboards have several limitations for prototyping circuits. However, most information found deals with parasitic capacitance such as to cause problems with higher frequency circuits. ...
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39 views

compute impedance from voltage and current measurements

I want to compute the impedance of my system from measurements of the voltage and the current. Is it simply the ratio of the rms amplitudes of the voltage and current (Z = Vrms / Irms)?
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23 views

Thevenin Impedance for network with only dependent sources

If a network has only dependent sources, you need to use a test current source or test voltage source (1v, 1a, something simple) since Zth = Voc/Isc doesn't work. Is it valid to use a DC source as a ...
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44 views

Transfer function in a 2L2C circuit

I have to find the transfer function of the following circuit (AC, sinusoidal), using complex numbers, Kirchoff point rule with potentials or Millman's theorem. The transfer function is ...
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2answers
44 views

Amplify and impedance match a low voltage signal

Situation: I am trying to trigger an external generator using the 1 Pulse Per Second (PPS) off a GPS receiver. The GPS receiver outputs a ~3.3Vp at high impedance once per second once the GPS receiver ...
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31 views

Multi channel variable speaker design problem

As part of my my consideration of possible solutions to my multi channel variable speaker number problem arising from my attempts to restore radio functionality to an old hotel intercom system (see ...
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62 views

Why should the output impedance of a current source be much greater than the input impedance of the load?

For a voltage source (except RF circuits), the output impedance of the source signal being coupled must be much smaller than the input impedance of the load. This is first of all done to prevent ...
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69 views

Does my PCB Require 50 Ohm Impedance trace even if i am using external antenna?

I am using the Quectel M95 GPRS Modem in my PCB, and the hardware reference guide says "The Pin 39 is the RF antenna pad. The RF interface has an impedance of 50Ω. " I am using a u.efl connector and ...
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84 views

.TF Spice Simulation, output impedance with current as output

So I'm currently reading CMOS by R. Jacober Baker and in the first chapter there is a quick introduction into Spice but I have a hard time understanding one of its examples. So this is the circuit: ...
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28 views

Measure Input Z of Tranformer with LTSpice

I would like to more accurately model audio frequency transformers in LTSpice. To that end I tried to verify the input impedance using a model like the following: This is supposed to model a ...
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1answer
59 views

Measuring Input Impedance of Transistor with LTSpice

How do you measure the input impedance of a transistor with LTSpice? Consider the following circuit: The above just biases a transistor so that the collector is 1/2 the supply. I used a current ...
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2answers
68 views

How many turns do I need for the primary coil of a transformer?

I need to know the number of turns that should be connected to 220 volts AC. I can measure resistance only, I don't have a device that measures inductance. If I need the primary coil to be 220V / 1A ...
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2answers
56 views

AC/Phasor Circuit Output Voltage Question

So we have a pretty simple circuit, just a 10V voltage source in series with an impedance of 1.8k ohms and a capacitor with a capacitance of 100nF. We're asked to check the voltage across the ...
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63 views

Cascading Common-Emitter Common-Collector for maximum power transfer

Hi Am trying to understand what am doing wrong, I connected CE to CC with a small Rload am designing it so Zout of the second stage equal Rload to get Maximum output. From what i read in CC-amp Zout ...
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52 views

Determining output impedance for a pulse generator

I have a basic question about determining the output impedance of a circuit. Output of this circuit is through R6 in the Figure above. This will be an input for a data-acquisition hardware channel ...
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1answer
102 views

How to route a trace on PCB with 50 Ohm impedance?

I used some online calculator to calculate parameters of trace so it has 50 Ohm impedance. I use FR-4, so H=1.5mm, T=0.035mm and Er = 4.5. 2-side PCB, one side with signals, the other with GND. I set ...
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195 views

How does the internal resistance of oscilloscope compare to that of the DMM? [closed]

Both are the instruments that measure voltage, so what are the difference between multimeter and oscilloscope in terms of their internal resistance ?
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1answer
37 views

Cancel resonation impedance of a speaker

In a speaker there is a resonace impedance. Now I am trying to cancel this out in order to create a flat impedance graph for all frequencies. I know this can be done by using a parralel zodel ...
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1answer
74 views

Voltage follower with a RF signal

I have a RF signal up to 50 MHz coming from a VCO which I want to use on a different impedance circuit. Without any adaptation the signal go down quickly when i raise the frequency because my load is ...
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2answers
68 views

Black box impedance…how do I test?

I have an audio circuit that I need to find the internal impedance of the circuit. How do I do this by only changing the output impedance of the circuit and taking measurements? I know I did this back ...
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45 views

What's the wire gage factor

in the following discussion: Why is AC impedance 1.3 times the DC resistance? Andy aka gives the solution and present equation with the wire gage factor (k) refer to some table. I want to know what is ...
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117 views

Why is AC impedance 1.3 times the DC resistance? [closed]

I have seen several times that AC impedance is considered to be 1.3 or 1.5 times the DC resistance. But, never found the reason behind this consideration. Is it an experimental or observational ...
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44 views

matching impedance of stm32f4-discovery board's DCMI to image sensor data line

Could you please let me know how to find input impedance of STM32F407 DCMI pins? I'm designing a camera module using sony's IMX224 image sensor. In the future this module will be connected to ...
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1answer
53 views

How do I set up speakers in series and/or parallel for a minimum 4 ohm load on the amplifier?

I need to connect 4 speakers to 1 output of a power amplifier. All speakers are identical (100 watts @ 8ohms) and the minimum load permissible on the amp is 4 ohms. They can be connected in series ...
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1answer
56 views

Determining the open-loop output impedance of a buck-boost converter. How to do it?

I'm currently working with a circuit that is slightly more complicated than a buck-boost converter, but for simplicity let's just consider the small-signal model of a standard buck-boost converter. I ...
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1answer
59 views

Impedance matching with transformer and resistor

I want to drive a 8Ohm load with a tube amp(Push-pull 2xEL84) that needs a ~8kOhm impedance on its outputs. I have a transformer that has a impedance turns ratio of 0,048. link So if I just plug in ...
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52 views

Transfomation of impedance using a balun

I need to convert 75 ohms balanced impedance to 50 ohms unbalanced impedance using a balun. How do I do that? I am new to this and don't really understand the concept of a:1 voltage and current ...
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1answer
150 views

Pin value of a GPIO pin set as high impedance

I am using an STM32F4 discovery board and my intention is to set one of its GPIO pins at high impedance, which I have done as below: ...
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1answer
69 views

impedance of an sine wave circuit

I would like to get some help with the calculation and modeling of the attached circuit. this circuit is supposed to generate a 159.15 Hz sine wave(according to formula), i want to connect the output ...
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2answers
213 views

Repercussions of choosing a poor audio amplifier

I have a customer who had an audio system setup in his business a couple months ago, and he's had some issues with it. The relevant bits are that one of the original amplifiers blew upon initial ...
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67 views

what kind of circuit structure can I use to obtain high output impedance?

what kind of circuit structure can I use to obtain high output impedance? In my design I need an amplifier whose output impedance is extremely high,which structure can do this? I read in Sansen's ...
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194 views

Measuring impedance of a DCDC converter

I am interested in measuring the output impedance of an high performance DCDC converter together with its board. Up to now I referred to this document, a very well written one. I am referring to ...
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168 views

why we must to follow 50ohm and 100ohm impedance in PCB boards? is it a standard value for all device input and output impedance? [duplicate]

In PCB / PWB boards we are following 50ohm impedance for single ended lines and 100ohm impedance for Differential lines? is it a standard value for all device input and output impedance? Each and ...
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1answer
36 views

Simple Analogy for Impedance and Load?

Can someone explain what impedance and load really are? I have a textbook in front of me and I have taken and passed the EE class on it, but aside from a textbook definition I can't seem to get a ...
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91 views

Simple NMOS transistor circuit output impedance

I am having trouble figuring out the best way to determine the output impedance of this simple NMOS transistor circuit: Both transistors are equal, and the body effect is ignored. What method ...
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2answers
76 views

Can I use a USB for four point impedance measurements

I'm not very familiar with USB's, but I do understand that usually there are four wires, a +5V, a GND, and D+ and D- for data exchange. What my question is, is that currently with a system that I'm ...
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106 views

How to calculate this Z= 4 || j2

is i(t)=5 cos(10t+40°) A. A resistor 4 ohm is parallel with an inductor 0.2H. ZL=j2 Z= 4 || j2 How do i calculate this?
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40 views

Modelling SWER in a 3 phase power system as a single condcutor

So there are two parts to this question, first can SWER (Single Wire Earth Return) be correctly modelled as a single phase? The reason I ask is the modelling program I'm using can't distinctly model ...
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1answer
72 views

Input impedance circuit

Please can you assist me in my solution if it correct. I need to know the basics if a negative resistor will change my node two equation? are my natural frequencies correct? Please help. Thanks.
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1answer
52 views

Amplifier input impedance matching to source (low frequencies)

I'm curious as to what the benefits are of having an amplifier's input impedance exactly matched to that of the source? For example, when measuring voltages, if the source impedance is between 500 ...
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3answers
278 views

Why is the Inductive reactance formula (XL=2πfL) not working for me?

I have an inductor labeled as "222" which I believe its means that its inductance value is equal to 2200 Microhenries. I double checked by measuring the inductor with and LCR meter and the value ...
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2answers
95 views

How does electrical interface on multi-subscriber FDM telephone line work?

I am wondering how the electrical interface for a frequency multiplexed telephone line works. If two senders are connected to a single line, how is it that the final output stage amplifiers don't ...
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1answer
45 views

As a voltage source voltage increases, how does the internal resistance increase?

As title says, supposes that maximum voltage of AC voltage source, or just voltage of DC voltage source, increases, because voltage source equipment is changed. What happens to internal resistance of ...
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235 views

How can we have high voltage and low current (in transformers), if V = I * Impedance?

I have researched a lot on this topic (including this site) and found this link somewhat helpful : How is it possible to have high voltage and low current? ...     But still it seems ...
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50 views

How can a signal backfeed and create a crosstalk in a passive summation circuit?

...a passive summation circuit can be a simple way to combine signals but one disadvantage is that the summed signal will backfeed into each of the sources. This could be an issue if you ...
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71 views

Placement of filter components to reduce EMI

An electro-magnetic interference (EMI) source is connected to a filter and to a LISN. The EMI source is a common-mode source: it generates an undesirable signal which flows from the generator \$ V_g ...
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42 views

Measuring impedance frequency response on Low Power Board

I have a low power board (2.1V DC). It runs a micro, some sensors, etc. I am interested in plotting out the impedance frequency response of the overall board so I can tell where the impedance dips. ...