Questions tagged [impedance]

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

161 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
3
votes
0answers
95 views

Electrical circuits homework

I am pretty new to circuits analysis and I have the following problem as homework: ig2(t) = 4sin(ωt + π/4), e3(t) = 12sin(ωt + π/4), R1 = 10 Ω, ωL1 = 4 Ω, ωL3 = 3 Ω, 1/(ωC2) = 6 Ω I have to calculate ...
3
votes
0answers
700 views

Connect speaker directly to Samsung Galaxy S6. Minimum impedance accepted

I want to connect an external (passive) speaker (3W/16 ohm) directly to my Samsung Galaxy S6 using the headphone jack. I want to do this on my bicycle using the smallest space possible. Connecting the ...
2
votes
0answers
98 views

Why the capacitive divider in this output stage?

I have this output driving stage, reverse engineered from a generic Chinese mist generator: The goal is to drive the piezo transducer with a given frequency (more or less 1.7MHz or 2.4MHz depending ...
2
votes
0answers
75 views

Common term for Resistance and Conductance?

Simple question; Impedance and Admittance are complementary quantities, and can be described by the common term "Immittance". Likewise Resistance and Conductance are complimentary quantities,...
2
votes
1answer
51 views

Differential and single-ended input impedance

I have this circuit and I'm interested in finding both the single-ended and differential input impedance. But is there even a difference? This is also at DC, so we can just ignore the inductors and ...
2
votes
1answer
201 views

Locally hatched ground plane to increase differential impedance

I am designing a flexible PCB to carry two types of differential signals. One is about 1.2Gbps 100R differential impedance, while the other is only 3Mbps, with much more tolerance on the impedance. ...
2
votes
1answer
115 views

Low-pass filter - choosing R values dependent on the load impedance

I need to design a low-pass RC filter that is connected to an oscilloscope at the output. The oscilloscope has a load impedance of 1MΩ||20pF. I have to choose values for R and C, taking this load ...
2
votes
0answers
65 views

Circuit Analysis: Difficulty in obtaining a current through a resistor?

I'm solving a problem that requires I compute some impedances, and then the current through a resistor. I obtained some of the impedances*, but don't know how to get the second part (current). ...
2
votes
1answer
249 views

How does at low power factor impedance (p.f=R/Z) (if R is constant ) increases while current also increases?

Impedance is equivalent resistance of circuit having resistive and reactive components so if we keep R constant and increase inductance than Z will increase and power factor will going to decrease as ...
2
votes
0answers
586 views

Admittance, Conductance, Susceptance definition

Admittance is the reciprocal of impedance. But: 1) Susceptance is the reciprocal of reactance, or the imaginary part of admittance ? 2) Conductance is the reciprocal of resistance, or the real part ...
2
votes
1answer
934 views

Output impedance of a series shunt feedback amplifier

I am trying to find the output impedance of a series shunt feedback amplifier by converting it to a two port network. I know the input impedance: Ri=ri*(1+A.β) But I dont know how I should find ...
2
votes
0answers
58 views

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 ...
2
votes
0answers
422 views

Parallel transmission lines impedance

I just want to know the correct way to calculate \$Z_{in}\$ in this network. It's very simple but I think I might be doing something wrong. Is it ok to calculate the impedance over one line and get \$...
2
votes
1answer
340 views

Equations governing the impedance of a generalised constant-phase element in the time domain?

I apologize in advance for the large wall of text, but I feel like to properly ask this question, some background information is in order. I've been recently working on modelling the impedance of a ...
2
votes
0answers
733 views

Bus interface for short distances, many device data exchange - CAN, RS485? + characteristic impedance and media capacitance

I ran into some troubles trying to design a wired bus which will connect in about 64 testing devices. My first choice of mind was CAN bus, known of it's reliability and low EMC interference. However, ...
2
votes
0answers
86 views

How do I perform an electrochemical impedance spectroscopy test for battery?

I have tried to look online for procedures to perform this test but couldn’t find anything. So if anyone can refer me to a set of procedures or give me procedures that I can use to perform the test ...
2
votes
2answers
179 views

Circuits of AC - impedance

I have a question regarding impedances. While it is intuitive that \$ R \$-element has impedance \$ R \$, it's not so easy for me to figure out impedances of \$ L \$ and \$ C \$. Here is my, probably ...
2
votes
0answers
92 views

Understanding amplitude-time peaks in one dimensional reflection and transmission of sound waves

There is a one dimensional system of interfaces with a transducer sending and receiving sound wave (Plane wave) normal to the interface boundary. The system consists of two mediums, medium 1 & ...
1
vote
0answers
17 views

Power consumption on LPDDR4 command bus - impedance options

I'm trying to solicit and opinion on the use of the 60 ohm transmitter/transmission line/ODT for the command bus of an LPDDR4 bus would be better than 40 ohm target impedance. The system uses an ...
1
vote
2answers
38 views

How do I incorporate output and input impedances connected to my circuit?

I'm designing a TTL to VGA DAC for a vintage PC, and I'm confused about the significance of the output and input impedances of my video card and monitor, respectively. The VGA spec states 75 ohms at ...
1
vote
0answers
37 views

Is it beneficial to use a taper for the feed input of a PCB antenna?

What is your opinion on using a taper for the feed input of a PCB antenna? Say the feed is 2mm wide and the transmission line is 0.45 mm. Would a taper just cause more impedance mismatch? Or would it ...
1
vote
1answer
38 views

RF via impedance calculation with NFP removal

I'm trying to match the impedance of a RF via from bottom layer to top layer in a 6-layer PCB design. GNSS signal. Unused pad (NFP) removal activated. The selected via size is 0.9mm pad and 0.5mm ...
1
vote
1answer
275 views

Xilinx FPGA and DDR3 Memory. Confusing Impedance combinations

Currently I'm planning on doing a PCB with DDR3 memory and an Artix7 FPGA. During my research a few questions accumulated. When looking at the reference manual of the Arty7 board, I see that I have to ...
1
vote
1answer
69 views

How to continuously vary inductance in the range \$[-A, A]\$, A>0?

I require an inductor whose inductance varies continuously as a function of some parameter \$p\$, like a bias voltage or something else that is easily user-controllable (not frequency as I require it ...
1
vote
1answer
52 views

Emulate impedance response using RLC components

I need to emulate measured impedance response of some blackbox using only RLC components. Measurements: ...
1
vote
0answers
140 views

Two port networks - Why are shared Z-parameters not negative?

In basic electronics we learned that to solve a circuit using mesh analysis, the shared impedances had to be negative. For example in the circuit bellow, the system of equations would be: $$\begin{...
1
vote
0answers
120 views

Impedance and resonance frequency of a bias tee

I am a beginner trying to learn about combining impedances and solving for the resonance frequency. I am solving a circuit: simulate this circuit – Schematic created using CircuitLab and I ...
1
vote
0answers
30 views

Transmission Bus Admittance Question

I have a question about calculating the admittance between buses in the single line diagram shown below: The solution I have been given shows that the admittance between bus 2-2 is found by adding ...
1
vote
1answer
301 views

The explanation about why do we define the formula of Characteristic impedance,propagation constant and Velocity propagation

There is a long transmission line 1.Characteristic impedance \$Z_C=\sqrt{\frac{z}{y}}=\sqrt{\frac{impedance}{admittance}}\$,and in the lossless line,\$Z_C=\sqrt{\frac{L}{C}}\$ 2.propagation ...
1
vote
1answer
74 views

Can I determine three circuit elements from an impedance curve?

I have impedance data (\$|Z|\$ and \$\phi\$) of a diode, measured at a fixed frequency but depending on the applied bias. The diode can be modeled as a series resistance \$R_s\$ and a parallel circuit ...
1
vote
0answers
40 views

Does transformer line side voltage varies with backup generator on load side running at from 0 to 100%?

We have a transformer of 750 KVA with 5.75% impedance. On the load side we have loads and a back-up emergency generator. This emergency generator is capable of supplying the loads and still export ...
1
vote
0answers
278 views

Twisted pair with shield and drain wire

Ive been posed with a problem regarding calculating the characteristic impedance of a shielded twisted pair with a drain wire. While I understand how to calculate this for a "normal" shielded twisted ...
1
vote
1answer
51 views

Inferring common mode impedance for a given CMRR

In the figure below, the common mode impedances of the line driver and receiver are represented by RCM+ and RC-: (What I understand by the phrase CM impedance is that it is the resistance or ...
1
vote
0answers
97 views

Dipole Antenna impedance and feed point, what is the effect of long distance to coax connector?

I have a folded dipole being made with a pair of twisted wires where each wire is 1/4 λ long and the dipole is constructed by twisting the centers of the wires so that the twisted pair is ...
1
vote
2answers
94 views

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 ...
1
vote
0answers
149 views

ngspice .measure syntax in AC + par()

Why do the two netlists give totally different output impedance values ? Netlist 1: ...
1
vote
0answers
47 views

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)?
1
vote
0answers
158 views

How do I refer an impedance from the delta side of a transformer to the WYE side?

My question is regarding the simple arrangement below: It is simply a three phase source feeding a load through Z1, followed by an ideal WYE DELTA transformer, followed by Z2. My question is how do ...
1
vote
1answer
319 views

Impedance mismatch in LISN for EMI/EMC test

I am currently designing LISN for CE-102 test.The schematic of the circuit is provided below. When I connect the circuit to the network analyzer the impedance is coming as shown below expected graph ...
1
vote
0answers
83 views

Need fast and exact voltage follower or divider cascade

Intro: I'm designing a makeshift oscilloscope and now need an input cascade for it (it is more fun project for me, rather than industrial-grade tool). The matter is I want to get something faster ...
1
vote
0answers
42 views

6 SPEAKERS one amp

I just joined stack exchange to ask this specific question. I have 6 speakers. All 6 are 8 ohm speakers. There are 2 pairs (Speakers 1&2 are pair A and speakers 3&4 are pair B and then 2 ...
1
vote
0answers
281 views

Ouput impedance of a balun

I am using the CC1110 RF IC and I am having trouble when matching the differential RF output impedance with the antenna. The datasheet states that the differential impedance seen from the RF output ...
1
vote
0answers
677 views

When are positive-sequence and negative-sequence equivalent impedance the same?

One of the topics we covered in an introduction to power systems class was using zero/positive/negative sequence networks to analyze faults in networks. For many problems, this requires setting up ...
1
vote
0answers
197 views

Antenna VSWR value and impedance matching claims by the manufacturer

Having larger value of VSWR is indication of improper matching. Eg. http://www.abracon.com/patchantenna/ACA-107-T.pdf this datasheet claims VSWR to be around 4:1 to 5:1 (which seems bad VSWR value to ...
1
vote
2answers
575 views

Differential impedance calculation: reference plane doubt

I'm calculating the width and spacing for my differential signals to meet impedance requirements. I have downloaded Saturn Impedance Calculator for making calculations. My pcb stackup has embedded ...
1
vote
0answers
7k views

How do I convert S-parameters for impedance matching?

How do I derive the Z-parameters to calculate a matching network for a device? I'm not sure what terms to even search for as I get all sorts of information I am not familiar with. My task is to ...
1
vote
0answers
106 views

What can I do to avoid impedance discontinuity when high-speed signal bifurcates on PCB?

As mentioned before, I want to supply two PCBs with same-frequency clock(as high as 10GHz).But now there is only one pair of differential clock, while both of the PCBs need one. So I am thinking of ...
1
vote
0answers
138 views

Without converting the secondary side to “Y”, how would one solve this question?

The question: "A three-phase 230 V, 27 kVA, 0.9 PF (lagging) load is supplied by three 10 kVA, 1330/230 V, 60 Hz transformers connected in Y-Δ by means of a common three-phase feeder whose impedance ...
1
vote
2answers
72 views

Did I wire this correctly? Trying to understand Thevenin and Loading of circuits

So right now I'm learning about RThevenin and VThevenin of a circuit and how to calculate what the voltage will be once you load the circuit. I am trying to build this circuit: I am not using these ...
1
vote
0answers
360 views

Calculate input impedance of transmission line without knowing L or C

I have the following problem: A TV antenna lead-in wire 10 cm long has a characteristic impedance of 250 ohms and is open-circuited at its end. If the line operates at 400 MHz, determine its input ...