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

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Wy are speakers rated by impedance instead of inductance?

Audio speakers contain coils which product sound by vibrating a cone. Why are speakers rated by impedance instead of inductance?
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26 views

L293D Motor driver 'braking' using input pins

I read the following on Wikipedia: Using pins 2 and 7 ( 15 and 10) to determine motor START/STOP or PWM duties it's dangerous, since there wouldn't be high impedance outputs: Current would flow ...
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22 views

Does the absolute sum of the elements of the imaginary part of the Y-matrix correspond to anything?

I have a simulation of a device with 4 ports (a double gated organic field-effect transistor), about which I also have some experimental data. I also made a simulation where I extracted the impedance ...
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1answer
34 views

Can I run a 450W Sub on a 1200W Amp? [closed]

Im considering purchasing this 450W RMS Subwoofer, can run it on this 1200W RMS Amp if I tune the settings correctly. SUBWOOFER SPECS POWER HANDLING RMS: 450 watts POWER HANDLING PEAK: 900 watts ...
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18 views

Different Op Amp output for battery/usb power

I'm using a micro running arduino to measure the resistance between two electrodes, connected to a dual op amp with automatic feedback control bias. The output is accurate when the circuit is powered ...
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1answer
32 views

Impedances to simplify RC circuit?

Suppose I am trying to solve the following circuit, where \$V_i\$ is the potential seen from the top branch to the bottom branch (which is 'grounded') and \$V_o\$ is the potential across \$C_2\$: ...
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100 views

How to calculate the output impedance of this circuit?

This is a hybrid-pi model of a BJT, and I want to know its output impedance: simulate this circuit – Schematic created using CircuitLab I know that I should short the input ports, place ...
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1answer
38 views

can the inductor and resistor values be found from the impedance

If the inductive impedance is given can the separate resistor and inductor values be calculated? OK The question gives the voltage supply (magnitude and frequency), power factor and current. It ...
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42 views

Input impedance of audio amplifier, unclear from datasheet

I have a AN7190NK audio power IC. It is a amplifier for the car radio. I want to know it's input impedance. In datasheet it states that: Input impedance ZI VIN = ± 0.3 VDC 28 kOhm I don't really ...
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28 views

Output Impedance of circuit

Please see image. Should'nt the output resistance be Rout = ro1 || ro3 rather than just soley ro3?
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34 views

Input power with PF, impedance on transmission line and transformer

I've just had and exam (Renewable Energy) and we had a problem that I'm not sure if is correct. The answers should be simple as we haven't studied tranmission lines at all. Okay, here we go. We have ...
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60 views

Impedance phase angle relative to?

In a simple PARALLEL RC circuit with two components of Resistor 150 Ohms and Capacitor 0.000000075F (75nF). AC supply 10V at 20,000Hz. Impedance has a phase angle of -54.7 degrees if my calculations ...
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62 views

Build own custom USB 'regulator' adapter board to solve Desktop boot hangs with KVM

My Desktop PC hangs in the BIOS boot phase when my KVM is attached. If I unplug the USB connecting the PC to the KVM, the PC boots without hanging. If the USB of the PC is connected directly to the ...
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2answers
83 views

Why is a shielded cable not effective with high impedance sensor?

Could some one simplify what this means? Why is the shielded cable not effective with a high impedance source/sensor?
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55 views

Impedance matching for piezo element

I am trying to boost audio signal from around 3V to around 60V for a piezo element with a component as small as possible. I found audio transformer MET-23 that reflects 1.6 kOhm impedance on primary ...
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1answer
67 views

What resisters for inverting op-amp should I use?

I am not an electrical engineer by any means so go easy on me here. I am simply experimenting with a speaker amplifier. My situation: I have a Clarion xc1410 4-channel amplifier with a 10k input ...
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2answers
44 views

Power calculation and Ohm's Law for Reactance

Hi I have the following question: V = 120V, I = 10 A, I lags V by 60degrees simulate this circuit – Schematic created using CircuitLab The load consists of a resistor and an inductor ...
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52 views

Circuit completes whether base current applied or not - transistor

My fourth electronics project ever. The most challenging yet. I've wired up this project (Project 4 - Short Circuits project kit Jaycar Electronics). After much research, it doesn't do what I ...
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1answer
52 views

Finding impedance Z and \$ \cos (\alpha) \$ in RLC circuit

I would like to have some help with this problem: U = 93 [V] f = 600 [Hz] L = 0,24 [H] C = 0,16 [μF] R = 950 [Ω] This is the RCL circuit which I need to find the impedance \$Z\$ in and ...
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1answer
94 views

This guitar piezo opamp buffer lacks any sort of bass, why?

My preamp in my acoustic guitar died after I put the battery in backwards. I need to replace it, and fast. Piezos have incredibly high output impedance (5+ mohm) so a buffer circuit is used to knock ...
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1answer
72 views

Understanding Ohm's law(?) for transmission lines

I have this easy schematic Next to this is stated that: $$Vb = \frac{Z_{in1}e_{b}}{R_{B}+Z_{in1}}$$ non Latex-version of the formula: Vb = (eb*Zin1)/(Rb+Zin1) I would like to know from where ...
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91 views

Set ADC input to high impedance

On a early version of the system I'm working on, an Arduino Mega was being used to read some analogue values using its ADC. Something critical to the application was for the ports to be always in high ...
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1answer
46 views

How to make an impedance matched circuit for fabbed antenna?

Okay I have developed an antenna for a system and need to create an impedance matching circuit. The theory of conjugate matching is simple, but actually implementing it is something I can't find ...
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Impedance Spectroscopy - Modelling a physical system as an RC network

I have a physical system which can (in principle) be modeled as a network of resistors and capacitors. To extract values of components, I am doing a frequency sweep and Fourier transforming, and ...
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28 views

Proof of formula to convert from parallel to series impedance

So, I tried to find a proof to the formulas to convert from parallel to series reactive circuit, which I found in the ARRL Handbook: \$R_s=\frac{R_pX_p^2}{R_p^2+X_p^2}\$ and ...
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Is this measurement of a cricuit's output impedance valid?

The following circuit is a simple voltage regulator. The Vout is maintained at -1V, however the opamp in the circuit has a non-zero output impedance. This is represented by the resistor R1. ...
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53 views

Power at the differential output

I was measuring the voltage at the intermediate frequency output of this tuner http://superkuh.com/gnuradio/R820T_datasheet-Non_R-20111130_unlocked.pdf using the oscilloscope. The tuner has a ...
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290 views

What does impedance control on a PCB mean [closed]

I understand that when the electrical length is less than 1/10 of the trace length I would have to go in for impedance matching. A PCB impedance is controlled by its stack up. THat is thickness of ...
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50 views

Getting the numerical value of a capacitor's impedance

I understand that the impedance of a capacitor is \$\frac{1}{j\omega C}\$. For the circuit above, I have \$\frac{1}{Z_V} = \frac{1}{Z_{V1}} + \frac{1}{Z_{V2}} + j\omega C_V\$ and \$V_V = ...
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82 views

Input/output impedance of microcontroller

how to calculate the input and out put impedance for a micro controller , for the purpose of modeling in LT spice , for example RX610 family from Renesas For example the lumped characteristics can ...
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1answer
37 views

Calculating Thevenin impedance

This is the circuit I'm given: And after disabling all of the sources, I'm now trying to calculate the equivalent impedance (which would be the Thevenin impedance): But I'm stumped on how to ...
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1answer
49 views

Impedance matching photon detector with multiple TTL counting devices

For my scientific work I wish to register signals coming from a photon detector which generates 50 Ohm TTL signals: The expected count rate will never exceed 4 MHz. The devices that need to record ...
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77 views

Is it practical to measure an unknown capacitance by measuring its impedance?

I've recently seen some fourth year engineering projects at my school (University of Waterloo) and one that I found interesting was this novel pressure sensor that uses nano silver separated by a ...
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49 views

PCB Trace Differential Pair Impedance

I'm designing a MIPI D-PHY interface, and the required nominel trace impedance for the differential signal lines (pcb traces) are 100 ohm. Can I create 100ohm differential impedance, by using two ...
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92 views

Measure AC power consumed by a loudspeaker

I'm interested in measuring the efficiency of a loudspeaker. I have tools to measure the SPL in dB. However, the electrical efficiency has me a little puzzled. The speaker has a voltage applied: ...
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69 views

Looking for a general, rigorous definition of “impedance”

Forget capacitors. Forget inductors. Forget resistors. Assume a generous background in elementary complex analysis and algebra. I'm trying to arrive at an elegant, minimalist, mathematically ...
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48 views

Physical interpretation of Re(Z) = max(Re(Z)) and Im(Z) = 0

I have plotted the real and imaginary parts of a device's input impedance with a VNA. What would be the best physical/electrical interpretation of the real part peak along with the imaginary part ...
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326 views

When do you need impedance matching?

Would anyone please explain why you don't need a controlled impedance board when you produce a PCB dealing with 50Mhz digital signal? I thought you might need a controlled impedance board, since 10Mhz ...
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1answer
25 views

How do I calculate the impedance of elements in a circuit given only equivalent impedance and angular frequency?

See photo included below. I've tried working this problem for an hour using phasors, voltage/current dividers, and Ohm's law, but I can't figure it out. It's given that equivalent impedance Z_eq = ...
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driving point impedance analysis to simplify circuits into one-port or two ports models

I have question understanding how to get Rthd and Rths. Could anyone help to explain ?
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74 views

How do I calculate the impedance needed to drop 120V AC?

I've been wanting to use the H11AA1 zero-crossing detector to detect the zero-crossing points of Mains Voltage - 120 V AC @ 50 Hz. The data sheet says that the max forward currents of the diodes are ...
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382 views

Twisted pair impedance

I've got a twisted pair cable that I'd like to use for connecting distributed systems that use 1Mbps CAN network. The problem is that I don't have a clue what's the impedance of this cable and I know ...
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38 views

Is the impedance controlled board necessary for my camera board?

Could you please let me know if my board needs impedance control? I'm designing a camera board using the IMX225LQR image sensor. After drawing schematic I contacted a company for PCB design and sample ...
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5answers
480 views

Resonance frequency of an RLC circuit

simulate this circuit – Schematic created using CircuitLab Is it safe to consider the resonance frequency of a second order RLC circuit to be alway equal to 1/sqrt(LC) or the transfer ...
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1answer
81 views

Transmission line, cable impedance

I am currently doing a design where I basically have two different types of (digital) signals. The first signal group is fully differential (P/N pair). The other group are single ended signals ...
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95 views

Calculating the voltage drop in AC circuit

I'm supposed to calculate the voltage drop (Ux). Where R=R=R=1kΩ, C=1µF, I=1mA, E= 2sin(ωt+pi/2), ω = 10^3 rad/s. I know I have to use superposition method, but I dont know how to calculate impedance ...
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37 views

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
50 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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48 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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2answers
59 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. ...