Questions tagged [coupling]
The coupling tag has no usage guidance.
2
votes
3answers
51 views
If a PEC surface completely reflects an EM wave, why doesn't an ungrounded shield work?
I was thinking about shielding and its effectiveness.
An ungrounded shield doesn't work well for either inductive or capacitive coupling.
However, if you think about plane wave theory, a PEC surface ...
0
votes
1answer
87 views
Coupling PCB traces
In my pcb design I have 2 triangular voltage signals with the following specs:
Peak voltage = 300V
Rise and fall time= 7us
Freq=25kHz
(assume a constant current of 0.5A)
Because of the limited ...
0
votes
1answer
67 views
Could shielding (not grounded) affect signal integrity?
I'm trying to shield 6 flat cables that give me some communication issues because I thought that there might be cross-talk or other sources of interference that cause the problem.
The shielding is ...
3
votes
2answers
104 views
How does placing cap between signal GND and earth GND solve common mode noise?
Thanks in advance for your time.
I am reading several articles about differential mode noise and common mode noise. Among which I found the below 2 pretty instructive:
https://www.murata.com/~/media/...
0
votes
0answers
45 views
Maximum ringing due to inductive coupling
Consider a bundle of wires carrying binary data and the worst case (or almost-worst case) scenario of them switching all at the same time. The wires with their partial mutual inductances would be ...
0
votes
2answers
76 views
Parallel inductive coupling approximation - coupling coefficient
I have the problem of a few independent current loops (wires) that on a portion of the circuit are close to one another so there will be inductive coupling between them.
Each wire, on the portion of ...
0
votes
1answer
56 views
Crosstalk between AC and DC
First time asking a question but I've come across something I just can't find the answer to. Whether or not it's because a silly question I hope to find out.
So I understand that with crosstalk ...
0
votes
3answers
100 views
How do I terminate a directional coupler?
I'm using a directional coupler for a radar application using frequencies of 5.3-5.9GHz. The directional coupler linked above is matched to a 50ohm characteristic impedance.
How do I terminate the ...
2
votes
1answer
74 views
Coupling coefficient variation in Wireless power transfer
Question regarding WPT compensation topologies.
I'm trying to make a inductive wireless power transfer system where the RX coil can move quite conisderably relative to TX coil and still transfer ...
0
votes
3answers
112 views
Why does the voltage induced in the receiver coil of this WPT circuit decrease when a load is added (in parallel)?
The following is a circuit that wirelessly transfers power via inductive coupling. The circuit is supposed to power a 12 V 0.15 A DC fan and a typical smartphone, which requires 5 V DC across it. The ...
1
vote
2answers
383 views
Mutual inductance vs coupling coefficient
Question regarding this and this question about mutual inductance and coupling coefficient.
I'm trying to analyse a two coil system:
It consists of two coils like in the picture with 2 cm air gap ...
0
votes
2answers
60 views
Is wireless technology only possible due to inductance?
I asked a friend how capacitative coupling works in glass-mount antennas.
He said it's like when installing a sound system; where you want to keep the power & audio cables separated, to avoid ...
0
votes
1answer
138 views
USB 3.1 AC Coupling Capacitor Implementation
How should the AC coupling should be implemented when connecting a USB 3.1 hub to a USB Type-C connector through a MUX. Is it:
Both sides of each MUX.
On the switched output of each MUX.
On the ...
0
votes
1answer
53 views
Why are inductively coupled RFID systems put in certain frequency bands when there are no EM waves used?
LF - 125 kHz
HF - 13.56 MHz
Those frequencies refer to the magnetic field that is used to induce a voltage in the transponder. Can the magnetic fields actually interfere with EM waves in the ...
0
votes
1answer
116 views
Help with design a mic preamp with opamps for PGA and ADC
I want to sample an audio source using an electret microphone and analyze the spectrum of it with a uC. I'm interested in the 100Hz-2.5kHz range, so I calculate with these values when I tried to ...
0
votes
3answers
81 views
RFID: Why is inductive coupling used instead of EM waves for LF and HF systems?
Is it because of antenna sizes? At 900 MHz a 1/2 dipole has a size of around 15 cm. That would be far higher for 125 kHz, so instead we use coils to power the transponder and use load modulation for ...
0
votes
3answers
287 views
AC coupling capacitor in the ground to break the ground loop?
I'm implementing the following audio single-ended to differential converter for an ADC:
This is the reference design for the PCM1804 that I intend to use.
What would happen if I do this:
Would it ...
0
votes
1answer
101 views
Can someone explain how frequency and inductance affects this pair of coupled inductors?
I am simulating this simple circuit on PSIM; a single-phase AC voltage source connected to the primary of a pair of coupled inductors, with a 12 Ohms load on the secondary side. I want to increase the ...
0
votes
1answer
48 views
Capacitive coupling: how to collect 60uA from this set-up?
I need to collect at least 60uA via capacitive coupling between a high tension Cu cable with PVC insulation and a connector that is acting as the opposite face of the capacitor (can be a copper plate ...
3
votes
2answers
247 views
How do coupling capacitors in transistor not affect biasing?
I understand the usefulness of the capacitors in an amplifier circuit but i dont understand why we use one at the input? and how does this not affect the biasing if it removes the dc voltage?
Thanks.
-2
votes
1answer
94 views
Series and Parallel RLC Circuit [closed]
I am trying to build a resonant circuit for data communication between coils.
Which would be better, a series or a parallel resonant circuit?
What is the difference between them and in which ...
1
vote
2answers
82 views
Is this phenomenon capacitive coupling or human antenna effect?
I injected a 90 MHz signal into an electrical cable via a signal generator. And I used a spectrum analyzer to measure the signal strength of 90 MHz at the other end of the cable. Then I found the ...
0
votes
1answer
54 views
Coupling between a cable and the main power line: how to measure it?
I'm wondering what's the simplest way to find the value of capacitive coupling between a cable and the main power line (230Vrms @50Hz, I'm in Europe) to use afterwards in some SPICE simulations. I ...
1
vote
3answers
495 views
Shock from Capacitive Coupling
In an AC supply which is not earth grounded, I see a small amount of current flowing to ground from both wires of the supply (live wire has higher) even though the circuit is incomplete.
It is due ...
0
votes
3answers
186 views
How to find coupling and decoupling capacitor values?
I am trying to learn receiver design, one thing I noticed is the use of coupling capacitors and decoupling capacitors and incuctors. There were set of standard values such as 100 pF, 1000 pF or 0.1 uF ...
2
votes
2answers
142 views
Crosstalk in analog switch
Art of Electronics, 3rd Ed, pg. 179, gives a model for the capacitive coupling between independent channels of an AD7510DI analog switch. The authors ask to calculate the coupling between channels ...
0
votes
1answer
255 views
SPICE modelling output/input coupling in ultrasonic transducer driver
The real device is this.
The LT SPICE model is here.
The schematic of the driver part of the circuitry (omitting power supply circuitry and relay circuitry that basically switches the driver between ...
0
votes
3answers
578 views
What does an RF coupler actually do?
I've spent a few hours reading about the basics of RF directional couplers, but I am still having trouble understanding just the very basics of what a coupler does. To start with, I've had difficulty ...
0
votes
1answer
62 views
Op-amp for audio-arduino interfacing circuit
Is it possible to use opamp of LM392 in this circuit for interfacing audio to Arduino? I had LM392 laying around so I tried it, but it doesn't work, the output is always exactly 2.50V. I am not sure ...
0
votes
1answer
149 views
AC coupling to ground in amplifer circuits
I have been told that this schematic will lead to a slow charging of C1 (on right) due to the flow of current from the rails of the opamp trickling into the signal line and slowly charging the ...
0
votes
3answers
218 views
Superimpose a High Frequency AC Small Signal on a DC Power Signal
I am facing a challenging problem with a circuit that I am currently working on, I would like others input and thoughts.
I have a DC power signal that I am injecting a AC small signal this mixed ...
0
votes
1answer
56 views
Input biasing and coupling calculations
I have a low frequency input signal 3-80 Hz that I am feeding into an inverting op-amp input. I am slightly confused as to what values I should choose for the following components - R3, C2, R4:
The ...
0
votes
1answer
461 views
DC and AC coupling peak-peak difference
I have been measuring signals in an oscilloscope and I have stumbled upon a practical exercise of calculating the DC offset of a signal. Basically what I did was turn on the DC coupling, take the ...
3
votes
2answers
779 views
Oscilloscope AC coupling and PWM signal
I made a traditional PWM signal generator using a 555 timer IC.
However, when I connect the output (pin 3 of the 555) to my oscilloscope and set it to AC coupling, the signal shown on the display is ...
3
votes
2answers
61 views
Ensuring certain amplitude level of RF signal on a PCB board
I have an RFIC which has an LO input. This LO input has rails 0V and 1V and the LO input should be rail-to-rail. The termination is on-chip and may not be perfect.
The LO comes from an off-board 90 ...
1
vote
1answer
335 views
Choosing capacitor for RF coupling
I want to couple 10W at 150MHz, 50 Ohms (before and after an RF switch). The PA is a RA08H1317M powered by 14V DC.
How do I choose an RF coupling capacitor?
I have found this answer, but it only ...
1
vote
1answer
294 views
Some questions about a magnetically coupled circuit
Below the RLC circuit on the left side by the help of a periodic impulse generator V1 generates periodic damped oscillations with a certain frequency, and the resulting oscillating current couples to ...
0
votes
0answers
136 views
Two cascade directional couplers
I have the following question regarding directional couplers. Below is the question.
My solution was to multiply the scattering matrices of both couplers as in the following
\begin{pmatrix}0&-\...
0
votes
3answers
135 views
Properties of an Ideal Transformer and the reasons behind them
Why should the magnetising reactance of an ideal transformer be very large i.e. approach infinity? What practicality does this imply?
0
votes
1answer
127 views
Power Line Communication
I am using an emitter and a receiver circuit in order to communicate through the power line.
The receiver circuit I am using is shown at the figure below and it uses the LM567 tone decoder to decode ...
0
votes
1answer
69 views
48V coupling into digital signal
I have a large thruster that requires 48V to operate, which I've provided through an isolated supply (Vicor DC/DC isolated converters). The thruster uses a Hall-effect sensor to adjust the speed (-5V ...
6
votes
4answers
3k views
Why is a resistor added after the DC blocking capacitor of the op-amp input? [duplicate]
I read somewhere that the addition of R2 provides the DC return to ground however this would reduce the overall input impedance of the op-amp. Input impedance must be high for an op-amp. How to solve ...
2
votes
1answer
77 views
Which one of these shielded scenarios is correct?
I have a system were both the signal generated and the sensing equipment is sharing the same ground.
Which one of these shield terminations scenarios is correct? (if any). I searched the internet for ...
0
votes
2answers
40 views
Coupling servo-motors [closed]
My application is a small robot-ic head - lets say for a scarecrow. It is going to be moved around frequently, during operation too.
I obtained a lot of these "hobby" servos that are used in RC ...
8
votes
2answers
819 views
Need help reverse engineering and understanding a small circuit
I am an electronic student, and one day I opened an energy meter I have at home called EM21, and found out that its body is comprised of two major components:
The meter body, that connects to the ...
1
vote
3answers
133 views
a standard method for flowing down EMC/EMI requirements to internal modules
EMC/EMI standards (conducted/radiated emission/susceptibility) are well established for system boxes. However there appears to be no standards, nor methods for deriving a specification for internal ...
0
votes
1answer
645 views
Adding a DC bias to an AC signal for amplification and measurement
I am trying to add a DC bias to this AC signal, but for some reason the schematics I found online for this do not work. The AC coupling is not happening.
I have simulated the circuit here: http://...
0
votes
1answer
334 views
Two solenoid coils and ferrite rod, how to calculate mutual inductance or coupling co-eff
I have two solenoid coils, one is wounded on ferrite rod and other is wounded in larger diameter in proxmity of ferrite rod, see picture. It is used as wireless comm (simplex) between RX and TX where ...
0
votes
3answers
108 views
Do wires need to share similar characteristics in order for crosstalk to occur?
My understanding of crosstalk is how a radio transceiver works. You basically tune your transmitter and receiver to a similar frequency in order to get a cross-coupling of energy (the transmitter's ...
0
votes
1answer
96 views
coils/Inductors in series for power transfer
I have an air core inductor that I want to use for resonant coupling purposes. This inductor has an inductance value of 500nH. Is it ok to connect another inductor with a value of 100uH in series with ...
