# Questions tagged [impedance]

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

994 questions
Filter by
Sorted by
Tagged with
27 views

### What would be the impedance of 4x subwoofers connected with 2 on the left channel, 2 on the right channel [closed]

I want to install 4 Dayton TT25 puck subwoofers on a gaming chair for my nephew (2 on the backrest, 2 under the seat). However I can't figure out what will be the total impedance so I can choose an ...
37 views

### Impedance of an embedded microstrip with different sub- and superstrate

I have been trying to find a formula to calculate the impedance of an embedded microstrip where the substrate has a different dielectric constant to the superstrate (so the stack up is conducting ...
72 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,...
39 views

### Single trace width calculator for impedance matching

I would like to calculate the trace width of a dipole PCB antenna in order to match a 50ohm impedance. Obviously, there is no ground on the bottom side. All the impedance matching trace width ...
36 views

### Bio Impedance Calculator circuit

I'm currently in a project which consists of making a bio Impedance meter with the AD5933. This could be a very easy project if I had to use the frequency range (1Hz->100kHz) that give the onboard ...
89 views

### Op amp circuit and input impedance

I am trying to understand this op-amp circuit that came from one of our suppliers. The input on X9 connector is a speed sensor (magnetic pickup sensor.) Its voltage amplitude is proportionnal to a ...
46 views

### Why can you measure input and output impedance of a amplifier circuit with a resistance/potentiometer?

While running simulations for a circuit I measured the input and output impedance by simply adding a potentiometer, turn it up until the voltage peak to peak signal going out reached half and then ...
39 views

### Characteristic Impedance vs Frequency

I am reading this paper and I see that characteristic impedance does not take frequency into account. I am surprised by this as I figured different rise time signals would have different frequency ...
63 views

### How can I calculate the voltage on the load with an UNUN (unbalanced-to-unbalanced) RF transformer?

I'm having hard time calculating how much RF voltage would be applied to the load in presence of an RF transformer (Unun with a specific ratio). Let me draw a simple circuit diagram. The AC power ...
100 views

### How would I find the transfer function of this circuit?

I know that I can take the inductor and resistor and find the impedance from them in parallel. But what do I do with the resistor, R3? Do I need to do a nodal analysis and solve for the Vout? Or can I ...
61 views

### PCB trace height to width ratio

I came across the Isola IsoStack website that lets me test PCB stack-up using Isola substrates: https://www.isola-group.com/isostack My project is using a stripline design with a 1oz copper inner ...
59 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 ...
45 views

### Initial value generator in a circuit (Anfangswertgenerator)

I am preparing for my electrical engineering exam and I saw this in my script. I have this first circuit and the requirement is to draw the circuit in Laplace with initial value generator where t > ...
30 views

### Vector Network Analyzers: Bode100 vs Keysight P5000A

I have been using Bode 100 machine earlier to measure Impedance and Phase of my piezoelectric transducer. The frequency range i work in is from 10kHz to 2.5MHz. I was just comparing this Bode100 with ...
610 views

### Pullup resistors. Does it make any difference what side of the series resistor?

The line is high frequency digital line. It has to be pulled up. Does the side of the series resistor make any difference? simulate this circuit – Schematic created using CircuitLab or ...
85 views

### Why does the length of the wire matter to the value of the pull up resistors?

In this DHT-11 datasheet the following sentence was mentioned (on page 4) A typical application circuit recommended cable length shorter than 20 meters with a 5.1K pull-up resistor when greater than ...
36 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 ...
75 views

### Ferrite bead isolation for FPGA core voltage

Why is the ferrite bead isolation not recommended for any FPGA core voltages. When we usually refer any FPGA schematics the voltages output from regulators are directly connect to FPGA without any ...
53 views

### How to calculate the input impedance and transfer function

I have the following circuit, that is used as a signal conditioning circuit in a audio system project. I am trying to calculate the transfer function and the Zin(input impedance) and Zout(output ...
83 views

### Maximal Cable length for a given Opamp

How can one determine the maximal cable length an Opamp can drive without getting unstable? The thing which leads me to this question is that the impedance of a cable changes over frequency. Means, a ...
117 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. ...
220 views

### Input capacitor stage of ADC

I was reading the datasheet of ADS1115. It has an input capacitor stage which it continuously charges and discharges to measure the voltage between AINp and AINn. It is written in the datasheet that ...
42 views

### Cable calibration one port

The Bode 100 vector analyzer has an automatic setup to perform a one port cable calibration with short, open and 50 Ohm load, before doing impedance measurements. All good. How is that actually done? ...
114 views

### Is there a difference between PCB trace impedance and transmission line characteristic impedance?

PCB trace impedance (equations) don't seem to take into account frequency, I have (previously) been considering this to be a characteristic impedance i.e the distributed impedance of the line 'viewed' ...
46 views

### Shift and reduce sinewave

I want to meausure the impedance of a sample of carbon, marked Rc in my drawing. On my FPGA I have a DAC which can provide 0-3 volts and an ADC that can read 0-3 volts. By reffering the positive input ...
59 views

### Impedance Equalization Circuit

With reference to the circuit on attached -- the zobel/ impedance equalization circuit. If we don't know the value of L, Is there any ways to calculate C' without knowing the value of L? I believe ...
192 views

### CAN Bus on PCB traces instead of twisted pair cable - points to consider

In order to save cost on the system in one of my current projects (no cables) I would like to eliminate the CAN cable and add traces to the PCB (one pair from left to right to connect the connectors + ...
53 views

### Not matching 50 ohm impedance

For my RF circuit (868MHz), I need 50-ohm impedance. When I calculate the impedance as PCB manufacturer layer stack-up, the impedance would be 66 ohms. How does this affect my RF circuit performance? ...
39 views

### Digital output drive signal integrity

I am designing a PCB with the ICS-43434, and would like to do, at least, some simple signal integrity simulations. I asked the manufacturer for impedance, IBIS or V/I curves, but they do not have that ...
57 views

### RF Matching Net

I am projecting a system that contains two RF chips, a LoRa SX1276 (915MHz) chip and a ESP32-D0WDQ6 (2.5GHz). In the schematic bellow, the ESP32 (2.4GHz) design has a matching net between the chip ...
89 views

### Zeroes of transfer function

In 'Franklin F kuo's book it is written that "The zeroes of transmission of the ladder occur at the poles of The series branch impendences or at the zeroes of shunt branch impendences" here ...
92 views

### RF Matching Problem

I am having some fundamental issues trying to create an impedance matching network for an 868MHz antenna, I have a PI network between the antenna's connector and the antenna feed point I have measured ...
65 views

### Arduino analog input value oscillating, why does the DMM work and arduino not so much

I am measuring voltage output from a device with 10 kohm output impedance with an arduino analog input pin. I see what I would expect with a multimeter, but with the arduino I get either garbage, or ...
56 views

### Controlled impedance traces necessary between line driver and series termination resistor?

I'm designing a line driver circuit with the SN74BCT25244 chip. The chip has a rise time of ~10 ns into an open circuit based on my own scope testing, but we are only wanting to drive the signal at a ...
36 views

### CAN Bus Nominal Impedance

I understand the reason for choosing a termination resistor of 120 Ohms for the CAN bus to avoid reflections but why was the nominal impedance of the CAN bus cables required to be 120 Ohms by the ISO ...
109 views

### Make a Negated General Impedance Converter

A General Impedance Converter (GIC) looks like this: Source: http://www.ee.nmt.edu/~wedeward/EE212L/SP15/ImpedanceConverters.html Where $$Z_{tot} = \frac{Z_1*Z_3*Z_5}{Z_2*Z_4}$$ But I need a circuit ...
68 views

### LDOs in series and impedance

I am unable to understand one thing. I have a 2 LDOs in series , the first a regular LDO with a normal impedance and second is a shunt regulator with an ultra low impedance . What will my load see... ...
56 views

### Why does my BA speaker truncate the negative part of the waveform?

I'm developing a custom earphone and I'm having some issues with producing a clean sound from my balanced armature (BA) driver (Sonion 31D005/8). I've come up with a pretty standard circuit (see below)...
94 views

### How to find the impedance of this RLC circuit?

I'm trying to find the impedance of this RLC circuit (sorry for awkward notation of Q instead of I and P instead of V due to that this scheme comes from an analogy of electrical circuits with 0D ...
74 views

### I need to measure the impedance of the system, is it better to measure the resistance or capacitance?

The goal of this project is to measure Retinol levels in the blood. To do this I will be use two electrodes, one of which will be coated in nanowires. These nanowires will then have antibodies that ...
56 views

### How to take my differential filter and design it for a different frequency and impedance?

I have a board with this differential PI filter: simulate this circuit – Schematic created using CircuitLab Say it's designed to pass signals with frequency X and bandwidth B1, and now I want ...
87 views

### Simple method to calculate output impedance of source follower

Output impedance of source follower without Rs would be 1/gm. However, if you add Rs the ...
109 views

### Impedance matching through via and signal trace of 2 layer board

Due to tight space constraints I need to pass my LTE signal (800-1800 MHz) through a via. The proximity between the antenna connector and the modem is very short (literally on the other side of the ...
5k views

### Why is impedance represented as a complex number rather than a vector?

I am trying to understand why impedance is not represented using vectors. I assume it is due to complex numbers having the property that $$j = \sqrt {-1}$$ but with my limited knowledge I can't see ...
94 views

### Impedance in sine DC

If we have a DC sine signal. Can we say that capacitors and inductors have impedance despite not being AC? If yes then what will the formula look like? And the opposite if we have an AC square signal ...
50 views

### Emulate impedance response using RLC components

I need to emulate measured impedance response of some blackbox using only RLC components. Measurements: ...
69 views

### How to choose speaker impedance for a VERY specific application?

Ok, so this may be a long post. I want to preface by saying I have very limited electrical engineering knowledge, so thank you in advance :-) I'm working on a medical device for a college project. ...
86 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 ...