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

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How Impedance at Frequencies affect Audio

I am trying to build an isolation transformer for my unbalanced 2 channel audio signal. How is Audio signal affected by different impedance's (of the transformer) over a frequency range? where: ...
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33 views

Series inductor as discontinuity in transmission line

Dual to this question is the following circuit: simulate this circuit – Schematic created using CircuitLab An infinite transmission line (with characteristic impedance \$ Z_0 \$) ends ...
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1answer
54 views

Shunt capacitor as discontinuity in transmission line

As in the following circuit simulate this circuit – Schematic created using CircuitLab suppose that an infinite transmission line (with characteristic impedance \$ Z_0 \$) ends upon a ...
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4answers
983 views

Why do characteristic impedances matter only when traces are longer than half a wavelength?

Why are characteristic impedances of traces not considered when the traces are shorter than half a wavelength? I've had the same issue with light diffraction, which happens when pinholes are smaller ...
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2answers
65 views

Input impedance of a non-inverting op-amp

From what I've read (and simulated), the feedback loop of an op-amp modifies the input impedance of the non-inverting input. The value specified in the datasheet is the open-loop input impedance, and ...
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24 views

transfer function of electric circuit

can Vo/vi = {1/1Fs/[1/1Fs +1/1Fs]} ( considering the capacitor's impedance)
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27 views

Calculating DC resistance from p.u. impedance

I need to calculate or approximate the DC resistance of a 208.5 km overhead line which has the following information: impedance per unit on 100 MVA base: R = 0.004 X = 0.047 B = 1.049 Is it even ...
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1answer
45 views

What is load impedance?

Like resistance for DC, Impedance is for AC. But what is load resistance. How does it used in a circuit. Had this doubt when reading a line from the book foundations of electronics by D ...
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48 views

Impedance matching routes in Eagle board

I am making my second board using Eagle CAD. I have different components with a set of different sizes. I set the minimum width for lines to be x. That way, the autorouter creates EVERY line in that ...
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2answers
309 views

Why are some common-mode chokes rated in ohms instead of henries?

Some common-mode chokes, including this one, are rated in ohms instead of in henries. Why? Isn't the impedance injected by the common-mode choke entirely frequency dependent? Is there an assumed ...
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19 views

Question about transformer reflected source

The following show the idea how a Thevenin equivalent source is used to replace the primary circuit of transformer. In textbook it is commonly stated that the load impedance sees an equivalent ...
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1answer
87 views

Bioelectrical Body Impedance Analysis?

On what principle Bioelectrical Body Impedance Analyzer works? I thought about this many times, and I wanted to know is there really a way to precisely measure all those body parameters with this ...
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1answer
59 views

one antenna working as receiver and transmitter

I want to know, if an antenna which transmits and receives the reflected signal can be modeled as an impedance. For example, the antenna is coupled to a Collpits oscillator and sends out an ...
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37 views

Wideband GHz impedance matching

I'm using an antenna that works in the range from 1 GHz to 3 GHz. I want to match impedances between a cable from the transmitter and the input amplifier and from the output amplifier and the cable to ...
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72 views

Circuit Impedance

What is the impedance of the following network? My textbook says $$Z = R_i + R + jwL + 1/jwC$$ But I can't seem to make that work.
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1answer
33 views

Impedance Matching a switching Circuit

I'm trying to mathematically model a Class E amplifier in the hopes of deriving a relationship between the input and output (Transfer Function). One particular difficulty i'm facing is impedance ...
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376 views

What does it mean for reactive power to be delivered / consumed?

Real power makes sense since there is actual consumption, but regarding reactive power; what is consumed / delivered? And how does the circuit change once this happens?
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68 views

Average alternating power

"For each of the values calculate P and Q" (average) V = 250 \$\cos (\omega t +45)\$ I = 4 \$\cos (\omega t -30)\$ The way I would try solving this would be by converting to phasors, taking the ...
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58 views

Impedance matching for a guitar pedal

So it's me working on a pedal again. I would like to add some equalizer effects on the pedal and found a fascinating circuit "Smash Drive": As far as I know, maximum power with lowest effect is ...
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1answer
37 views

adding parallel Impedance 1

A homework problem tells me to find the equivalent impedance, so I added the series and parallel impedances just like I would a resistor; however, I don't understand how does one go from ...
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1answer
23 views

How to test for Bioelecetrical impedance in an body fat analysier

I have an interesting project for school. I want to test these body fat machines for consistency between different brands. Ultimately to see if a cheaper brand is as good as an expensive one. ...
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3answers
69 views

Back reflections at low frequency?

Say I have a signal driver operating at 50 ohm output impedance, driving something with high (hundred kilo-ohm) input impedance. If the wavelength I'm using (a few kilohertz) is much longer than my ...
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2answers
196 views

Schematics: Effect factor and impedance

I have a questions regarding a simple schematic. I would like to calculate the total angle (φ) and power factor (cos φ) of this circuit and the total impedance (Z). -- Not using the complex-method ...
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3answers
92 views

Op-Amp based guitar direct box

I successfully built an active DI box using this circuit (image posted below), everything went fine and I'm happy of the result. Parts List ...
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34 views

Operational Transconductance Amplifier Input Configurations

I recently purchased several OTAs (Lm13700) but have had quite a bit of trouble using them. Going through the TI datasheet and a Nuts & Volts tutorial it's occured to me that transconductance amps ...
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1answer
33 views

How do you account for receiver sensitivity in tranceiver half wave dipoles?

if you are to design 2 halfwave dipoles, both can transmit to each other using 3 watts and have receiver sensitivity of -80dbm (a picowatt). Suppose they are 800m and have same height from ground. How ...
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34 views

Boost Converter High output impedance

at no load my boost converter, will be the same as in the photo. I'm thinking without a load at the end of the boost circuit the output impedance will be very high which will make the potential ...
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3answers
84 views

Frequency response of a complex circuit

I am interested in finding the impedance as a function of frequency of the \$n^{th}\$ circuit in this series: simulate this circuit – Schematic created using CircuitLab (By request: this ...
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135 views

Calculating resistance and reactance of an coil (motor winding)

I want to find out the resistance and the reactance of an motor coil. I can measure the magnitude of the current through the coil using a DMM. For example, If the voltage across the coil is 230v ac ...
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699 views

Should each trace carrying RF be 50Ohm in characteristic impedance? How?

I have to translate a VHF (160MHz) receiver schematic into a PCB. After looking here and there, I am a bit confused. It seems like the main issues with RF are to avoid stray inductors and ...
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1answer
69 views

Interfacing a GPRS chip (WISMO218) with an RF antenna. Calculating line width for the right impedance

I want to interface the WISMO218 GPRS chip with an antenna. The antenna lines on the PCB board have to be very specific, otherwise the system won't work. I have uploaded the part of the datasheet that ...
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2answers
305 views

Finding the schematic of a black box with unknown impedances

I'm struggling with trying to understand a piece of homework in Electrical Engineering that I'm really trying to solve on my own but now I'm basically stuck. The assignment is to find the schematic ...
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2answers
60 views

Solving for the impedance and phase shift in a series-parallel AC RCL Circuit with Complex Numbers

Having a lot of trouble working through an AC circuit, asking for some help. The circuit is relatively simple - I have a capacitor of capacitance \$C\$ and resistor of resistance \$R\$ hooked in ...
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1answer
61 views

Why does ceramic capacitor ESR change with frequency?

In most datasheets, I see a typical table which shows that ESR of ceramic capacitor changes with frequency. I understand that impedance of every kind of capacitor must have a minimum due to its ...
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3answers
80 views

What is Source Impedance?

I was going through data sheets of op amps and saw that bias currents usually add unwanted voltages due to voltages generated from the bias current flowing through the source impedances. What exactly ...
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239 views

How do utilities calculate transmission lines impedance?

I'm an electrical engineering student getting into Transmission Circuit Analysis, and a question came out to me: How do utilities measure their transmission lines impedance? Do they use special ...
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1answer
76 views

Matching the impedance of a filter?

Currently designing a circuit consisting of 50 Ohm rated ICs. Between two ICs (switches), I will place a BP-filter made out of discrete components (high-Q inductors and capacitors). The filter will ...
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2answers
129 views

Output Voltage Swing vs. Load Resistance of an Op Amp

What does the "Output Voltage Swing vs. Load Resistance" signify? Lets say I want to get a gain of 400 from an op-amp. I can use any one of the following combination Gain = -(R2/R1) Case 1: R2 = 400 ...
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93 views

How do I find the input impedance a common emitter amplifier?

How do I find the input impedance of this common emitter amplifier? \$V_{CC}\$ is supposed to be at the top of \$R_5\$. I forgot how to do the analysis to find the input impedance. The input goes ...
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4answers
109 views

What is an impedance in AC circuit? (Preferred simple answer) [closed]

Can someone please help me understand what an impedance in AC circuit, please? I have read so much about it still I having time understand it. How does it affect the circuit, is it good or bad for ...
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1answer
83 views

Question regarding electrical resonance/impedance [closed]

Me and my friends are currently working on a project where we have basically soldered a microphone unto a circuit with a small laser pointer. We have a reciever circuit consisting of a photo resistor ...
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3answers
272 views

How can I analyze an op-amp based negative impedance converter in a circuit?

I am thinking of the circuit pictured below, which, while the op-amp is operating in its linear region, gives rise to the relation $$ v_0 - v_1 = -i_0 r , $$ where the direction of positive current ...
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2answers
104 views

Wind high impedance transformer at home

Suppose I need to make transformer at home, but I am unable to wind 100k turns obviously, then can I just connect a resistor in series with a winding to achieve desired impedance? Will it have serious ...
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216 views

Output Impedance of BJT/Mosfet amplifiers

I have heard in lectures that the desired output impedance for the BJT/Mosfet Amplifiers is LOW. But these transistors are Transconductance amplifiers 'by birth'. I mean they give output current ...
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2answers
100 views

What is the 'characteristic frequency' of a certain impedance?

I'm not familiar with that term. Could somebody explain it to me? Is it the frequency at which the phase of the AC current running through the impedance goes to zero? Edit: Here is the context in ...
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1answer
63 views

impedance matching single vs series capacitor

Im looking at a impedance matching circuit on a schematic that shows a .75pF capacitor pulled to ground. With my current board design I have a 1pF and a 3.3pF on the board already so I am thinking ...
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104 views

From RLC prototype to signal flow graph

This simple 3rd order low-pass circuit simulate this circuit – Schematic created using CircuitLab can be described with the following 3 equations: $$-V_1 = \displaystyle \frac{-1}{sC_1} ...
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2answers
391 views

How to measure trace impedance?

I have seen that trace impedances in PCB's are maintained 50 ohm & so on. How to measure this impedance using a simple multimeter?
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2answers
125 views

Why is power reflected when there is an impedance mismatch? [duplicate]

I understand that when there is an impedance mismatch between an output stage, for example from an amplifier, and an input stage, for example, a transducer; power is reflected. I would like to know ...
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2answers
131 views

Op amp circuit design

I am having trouble with understanding how to design circuits involving op amps. I need to design a circuit using as less op amps as possible which has the following characteristics: high input ...