Questions tagged [coupling]
The coupling tag has no usage guidance.
125
questions
0
votes
0answers
20 views
Ac current injecton to dc bus
I want to inject a 2V ac sine wave on a 480V dc bus. to protect my ac signal generator from entering high dc voltage I am going to use capacitor as coupling device. Ac generator also should deliver 15 ...
0
votes
2answers
52 views
AC coupling of a transistor
So we assume to have proper bias currents flowing in both of the two transistors. What is claimed by books is that a capacitive coupling will not change the bias parameters.
But, we know that a ...
1
vote
0answers
39 views
Royer oscillator - frequency shifting in WPT
I am having a problem with my WPT resonant application. In my circuit modified Royer oscillator feeds LC tank. Receiver coil nearby is connected to rectifier and variable resistor. I know about ...
2
votes
2answers
56 views
EMC - conducted emissions - unused wires in cable - puzzling coupling
I am trying to understand the impact of unconnected wires in a cable for EMC conducted emissions tests.
My product has a shared unshielded cable for supply and communication (I know it's bad practice....
0
votes
0answers
34 views
Where is the capacitive coupling in this adafruit soil moisture sensor?
Here is the moisture sensor:
https://learn.adafruit.com/adafruit-stemma-soil-sensor-i2c-capacitive-moisture-sensor/downloads
It has a large copper area insulated with soldermask that sticks in the ...
0
votes
0answers
45 views
Understanding Ac coupling in this circuit
I'm simulating the circuit below in LTspice and there's something I don't get regarding C3 and C4. Suppose the input signal is a 32 uArms 60Hz current as shown. This value multiplied by the burden ...
0
votes
0answers
59 views
How to measure capacitive coupling on pcb traces?
I have bare PCB board (6 layers) with me and I would like to see if my switching signals (60 kHz) have any effect on the sensitive current measurement lines.
I just want to know if there is quick ...
0
votes
1answer
60 views
How to calculate cutoff frequency for a high pass filter in DC biasing circuit
I would like to DC bias an AC signal using a voltage divider as shown in the following schematic. I realise the bias point would be subject to noise from the power rails, but that is not a concern for ...
0
votes
0answers
28 views
Finding effective mutual inductance between a parallel inductors and a separate inductor
The effective inductance of two parallel coupled inductors can be calculated as
\$ L_{eff} =\frac{ L_{1}L_{2} - M_{12}^2}{L_{1} + L_{2} - 2M_{12}} \$
where \$L_{eff}\$ is the effective inductance ...
0
votes
1answer
50 views
Coupling coefficient of microstrip resonators
I am working in HFSS and I'm trying to determine the coupling coefficient between two microstrip resonators (k) so that I can design a filter using a certain resonator shape. I have the formula I need....
1
vote
2answers
96 views
Unintentional capacitive coupling
This question comes from text from the AOE 3rd ed. It's about unintentional capacitive coupling right after differentiators in chapter 1. I've included the text. Please read the first excerpt. That is ...
0
votes
1answer
25 views
Does DiSEqC require a DC bias?
The DiSEqC (Di[gital] S[attelite] Eq[uipment] C[ontrol] specification (bus_spec.pdf within https://www.eutelsat.com/files/PDF/DiSEqC-documentation.zip) describes a tone-based serial data bus that can ...
0
votes
0answers
21 views
Deriving equations for coupled line transmission line for even-odd modes
Is V2e = V1e ļ¼ V2o = V1o ļ¼
If not, how would we arrive at equations relating {V2e, V2o} to {V1e, V1o} respectively ?
0
votes
3answers
115 views
Shifting level voltage of a signal
I have a signal, which can vary from 400 to 7000 Hz approximately. It is a kind of pwm signal and has the time of high level, Ton, 30 times longer than the time of low level, Toff. The shape of the ...
0
votes
3answers
110 views
Adding small AC signal to a DC current using inductive coupling
Is it possible to add a small AC current on to a DC current in a wire using inductive coupling from an external source. Or if there is another way, I want to add AC ripples to a DC current.
simulate ...
1
vote
1answer
55 views
What grounding should I use for this capacitively coupled input?
I'm designing a device that will receive and digitize analog video signals. In analog video, it's recommended to capacitively couple inputs. A typical input might look like this:
In this case the ...
0
votes
1answer
103 views
2n7000 used for inductively coupled load modulation apparently latched
So I've got a fairly basic circuit set up for load modulation of an inductively coupled circuit:
A few notes on the above: LC's were designed for 1 MHz but work better at 950 kHz, thus the chosen ...
1
vote
0answers
41 views
How to find Q of a quarter-wave resonator loaded with a coupled-line coupler
I have a quarter wave resonator at frequency \$f_0\$ and characteristic impedance \$Z_{res}\$, which is coupled to a 50 Ohm load via a segment of coupled-lines coupler whose electrical length is \$\...
0
votes
4answers
230 views
AC-Coupling on Composite video
Many sources say that composite video input should be AC-coupled. Voltage levels for blank, black and white signal are also specified. How is it possible to detect these voltage levels after AC ...
2
votes
3answers
91 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
232 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
92 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
388 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
54 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
239 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
118 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
259 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 ...
3
votes
1answer
115 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
190 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
1k 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
67 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
483 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
56 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
237 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
103 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
740 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
156 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
52 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 ...
4
votes
2answers
468 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
339 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
99 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
82 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
794 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
469 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
255 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 ...
1
vote
1answer
498 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
2k 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
90 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
3answers
632 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
65 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 ...
