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

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75 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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46 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
63 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
40 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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2answers
51 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
50 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
86 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
71 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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1answer
79 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
40 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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0answers
32 views

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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19 views

Impedance in ideal electronic components [duplicate]

Why is it desirable to have Infinite input impedance and zero output impedance in electronic components? I thought of this question while studying the characteristics of an ideal OpAmp.
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1answer
27 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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2answers
42 views

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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1answer
51 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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2answers
278 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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2answers
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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3answers
80 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
30 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
46 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 ...
3
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1answer
75 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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1answer
46 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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4answers
85 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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54 views

Relation between input power and impedance in speakers

I'd like to understand what the relation mentioned in the title is. More specifically: I have to replace my metronome's broken mini-speaker rated 16 \$\Omega\$, 0.3 W, and the only replacement speaker ...
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2answers
68 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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41 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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2answers
322 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
23 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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15 views

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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2answers
69 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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371 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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2answers
37 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
457 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
71 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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94 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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1answer
35 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
47 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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1answer
38 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
53 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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1answer
43 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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1answer
28 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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1answer
48 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
54 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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38 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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88 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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1answer
128 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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1answer
96 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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1answer
242 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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120 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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72 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 ...