# Questions tagged [impedance]

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

788 questions
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### samsung galaxy phone jack pinout to pc

I'm trying to get the audio-out from a Samsung Galaxy A4 into a PC for recording with Audacity. I've tried a 3.5mm 4-pin (TRRS) and 3-pin (TRS) cable into the MIC input jack on the PC but none of them ...
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### Impedance calculation from voltage and current (exponential) waveforms

If we want to find the impedance across two terminals (a port) at a frequency $\omega_0$ using the voltage waveform across $v(t)$) and current through ($i(t)$) the terminal, general intuition is ...
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### Smith chart of λ/4 Transmission Line

I came across the following slide on power combiner circuit and I have questions about it. Why traverse across the upper half circle ? Why "ZT-line is the geometric mean of Zout and Zin." ?
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### Converting a headphone output to line level

I have a guitar amp that has a headphone output. I would like to convert this signal to line level so I can use it in a small mixer along with other line level signals to be heard in "in ear" style ...
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### Strange opamp's output impedance in spice

I'm simulating this circuit in Micro-Cap, which is the clipping stage of a guitar effect. The opamp model is the "NE-5532" I want to measure the input and the output impedance. I expected an output ...
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### How to achieve 100ohm impedance for HDMI differential pair on FR4?

I have a 6 layer FR4 PCB, and want to achieve 100ohm impedance on HDMI differential pairs. I am only using top and bottom layer for differential pairs, and following are my parameters: Trace width= 3....
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### Impedance/capacitance measurements

I'm trying to do some impedance measurements on passive components with the simple circuit shown below. I find it difficult to make sense of the results and hope somebody can help me understand what I'...
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### Any equivalent load circuit when an animal is connected to a current injector?

When the human body (chest, arm, etc) or an animal (limbs, belly, tail, etc) is connected to a circuit, I think this acts as a load. For instance, people simply model the connection between the AED (...
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### What does input/output resistance/impedance mean?

This keeps coming back in every single class, and I still don't have a clear idea of what it is. I keep seeing certain statements in other explanations such as "seen by X", "looking into Y" and so on. ...
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### How to convert this single ended output to a precise impedance balanced output?

This amplifier suits my purpose with one matter that I couldn’t figure out. Its output impedance is given as 0.01 Ohm. The output of this amplifier will be coupled to a very high input impedance(more ...
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### Is high current in a speaker the same as high voltage?

I'd like to build my own Amplifier, and because I know that the current creates the magnetic field, I don't understand, how amplifying the voltage makes it louder. I mean with high voltage doesn't ...
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### Passive band-pass filter conceptual analysis

I'm trying to chain a high-pass filter and a low-pass passive filter together to form a band pass filter to illustrate how you can combine filters together, but I'm having issues trying to understand ...
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### Calculating voltage loss using impedance of a system

simulate this circuit – Schematic created using CircuitLab So I'm trying to figure out the Total impedance Z of a system with a capacitor in series with a resistor and inductor, where the ...
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### Confusion between Input/Ouput Impedance and Thévenin's theorem

I'm bit confused about what Input Impedance or Output Impedance is. I tried to read Wikipedia's page (https://en.wikipedia.org/wiki/Input_impedance) but I find it hard to follow. Is the Input ...
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### Cut-Off Sinusoid or Sinuosoid?? - Standing Voltage Waves on Transmission Lines

My textbook shows two diagrams that appear to contradict each other to me. Each depict the magnitude of the standing voltage waves on a transmission line. The first, fig 2-14, shows a sinusoid bounded ...
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### Output TX Power with complex impedances

I'm developing an application with my software defined radio (SDR) Board and it is very critical that I have some control over the actual power I am transmitting at every time. In order to do this, I ...
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### Difference b/w Symmetric and Reciprocal Networks

A circuit exhibits symmetry when interchanging ports across a plane of symmetry results in no change in the impedance, admittance or scattering parameters of the circuit. Reciprocity also means ...
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### How do transformer obey Ohm's law?

I am honestly confused, A transformer "Steps up the voltage and steps down the current" or vice versa. So how does it obey Ohm's law? for example, a transformer with a winding relation of 2:3, should ...
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### Can I connect a 16 ohm output signal to a line input if I use a resistor in series?

newbie here. I have a Hi-Fi system and I wish to connect its output to a line input in another system while still being able to hear through the Hi-Fi´s original speakers. If I use the Headphone ...
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### Low-impedance tap in this oscillator circuit

Here is the schematic of Michigan Mighty Mite, a popular transmitter circuit design. It seems to be quite close to a regular feedback oscillator, with a few peculiarities. What puzzles me is the ...
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### How to quantify the cable impedance for common mode voltages?

Since a coaxial cable is not twisted, in the case of a common-mode interference the positive and negative lines will pick up different voltages. This unbalanced impedance nature of the cable can be ...
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### Controlled Traces Length in SD card

I my new design I need to use SD card communication. I would like to match all the impedance traces and control the length of the traces. Regarding the controlled length, is there a rule of thumb to ...
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### Induction heating

I was reading the working principles of induction heating and I think I understand the basics. Out of curiosity, I searched the Internet for a schematic and found one. However, the thing that confuses ...
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### Problem understanding impedance measurement device accuracy format

I am reading the datasheet of an impedance measurement device. Its accuracy is listed as '±0.4% rdg. ±8 dgt.'. What does 'rdg.' and 'dgt.' mean? And how should I interpret the accuracy? The device is ...
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### Input and Output Impedance of a SAW Filter

I am reading the datasheet of a SAW Filter B39162B4348P810. The datasheet doesn't say much about impedance of Input and Output ...
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### HB100 microwave sensor impedence question

The patch antenna on these are minimal. I would like to cut the feed point and tap it with a short length of UT141(?) to feed two 10 GHz horns. Does anyone have a guess as to the feed point impedance? ...
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### Difference between horn and power resister?

I have a circuit where my microcontroller is turning off and on a heavy load using a power mosfet (I've also tried it with a mosfet and a relay which yielded the same results). When I use a power ...
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### LVPECL termination impedance

I'm designing a level converter PCB using a LVPECL driver (ADCMP573) and a LVPECL-to-LVTTL translator (SY89323L). I'm reading a document about LVPECL termination schemes and there's something unclear ...
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### Determining Impedances of an Op-Amp Circuit

I'm trying to review some old concepts, and thus far, there was one that I couldn't really understand: impedance of circuits involving op-amps. Assuming an ideal op-amp, it has infinite input ...
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### How to read high impedance on pin Arduino?

The goal is to catch an AC leak. For these purposes, I use a measuring transformer (RCMB121). When there is no leakage, the output contacts are low (GND). If an accident occurs, the contacts go into a ...
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### Finding input impedance of the circuit

I'm having difficulties finding complex impedance of the following circuit: What I did first is find the impedance of $C$ and $R$ in parallel, which is: \underline{Z}_{CR}=\frac{R}{1+j\omega CR}...
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### How to design an impedance meter?

I am designing an impedance meter with NI devices. I am applying 0-20 uA current signal to an RC circuit and measuring the voltage. Impedance is calculated by dividing Vp-p by Ip-p. I am controlling ...
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### ngspice .measure syntax in AC + par()

Why do the two netlists give totally different output impedance values ? Netlist 1: ...
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### Ideal Transformer Theory Question

I have some questions regarding ideal transformers, similar to the one seen below: When talking about 'ideal transformers', can I calculate the current on the primary side by finding the complex ...
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### Is 'R' in impedance equation an AC or DC resistance?

I am using an impedance meter to measure impedance in complex form (R-jX) and an RLC meter to measure R & C values in an RC circuit. The value of DC resistance is equal to the R value in impedance ...
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### Confusion with output impedance using h parameters

Regarding the below liner circuit model, as far as I understand to find the output impedance the input current Ib is set to zero and the output resistance is calculated as Vc/Ic. I think this way of ...
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### What is a high impedance low level signal?

What is a high impedance low level signal? (I'm reading the circuit designer's companion by Peter Wilson)
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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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### Is it possible to realize an 1:16 impedance ratio Transmission Line Transformer on a single core?

I would like to build a wideband amplifier with a 1:16 impedance ratio Transmission Line Transformer (TLT) at the output. The input port of the TLT accepts a differential signal and provides a ...
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### Why it is necessary to put two 120 ohm termination resistors at each end of CAN transmission line respectively? [duplicate]

Why it is necessary to put two 120 ohm termination resistors at each end of CAN transmission line respectively? Does it make an equivalent resistance of 60 ohm? (parallel resistors). Is it OK to put ...
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### Do Germanium BJTs have lower impedance than Silicon BJTs?

What brings this up is the fact that Germanium has a higher electron mobility than Silicon(as well as lower barrier potential) and does that translate to greater admittance(including susceptance)?
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### Does impedance balancing in the far end make no sense?

Below shows a conversion of unbalanced line to a balanced one: My question is about: if the unbalanced line is very long which means the signal source and the isolation amplifier is apart from each ...
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### Output impedance of STM32H743 MCU?

How do I find the output impedance of the STM32H743 (and potentially other similar devices)? I've looked through the datasheet (DS12110 Rev 5) and the reference manual (RM0433 Rev 5) however haven't ...
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### measuring output impedance of op-amp

I've just took for granted the fact that the input impedance of op-amp is high and output impedance is low. I was reading "the art of electronics" lab book and there is an exercise that asks you to ...
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### In Impedance track algorithm, How is resistance is related to soc(state of charge)?

In impedance algorithm for battery capacity, why we are calculating impedance and why it important to know impedance for SOC(state of charge)? 2.I doing some research on algorithms which we have,so,...