Questions tagged [coupling]

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Optimizing AC capacitor coupling for enhanced DC filtering

I need assistance in refining my AC capacitor coupling circuit to effectively filter the DC component of my input signal. The circuit consists of a current generator, a 1 Ω resistor, and an AC ...
Morena Fabozzi's user avatar
1 vote
1 answer
129 views

Forms of Magnetic Noise Coupling

I was watching a video of Bob Pease discuss magnetic coupling of noise into the ground lead of an oscilloscope probe. See video at 5:40 https://www.youtube.com/watch?v=2vzvWUqUtb8 I noticed another ...
mrbean's user avatar
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5 votes
1 answer
155 views

How should I select appropriate capacitors to ensure compliance with IEC/EN 61000-4-2:2009 and IEC/EN 61000-4-5:2014 standards for my device?

When applying the IEC/EN 61000-4-2:2009 and IEC/EN 61000-4-5:2014 standards for our device, our consulting firm recommended bypassing the input power jack to the chassis ground using two 33nF ...
Sepehr's user avatar
  • 148
5 votes
4 answers
1k views

Would a room-sized coil used for inductive coupling and wireless energy transfer be feasible?

My understanding of inductive coupling is that it isn't feasible over long distances because the spread of the magnetic field lines happens rapidly, so not much flux will go through the receiver coil ...
Whelchel's user avatar
  • 153
0 votes
2 answers
65 views

Inductive crosstalk mechanism for 2 lines that run parallel on the same layer

According to Faraday's law, changing magnetic field lines that penetrates the victim line must create voltage on the victim line, but if we imagine, we see lines are orthogonal to the victim trace ...
dsplover123's user avatar
0 votes
0 answers
48 views

pspice error when coupling inductors

I am trying to simulate a simple transformer circuit in pspice v9.2. The circuit is based on pspice documentation here coupling settings: But running the simulation results in some errors: ...
mehdi's user avatar
  • 151
4 votes
1 answer
231 views

How does energy travel in the system in a conducted RF immunity test,?

I have a question regarding some conducted RF immunity (IEC 61000-4-6) tests. We inject noise starting at 150kHz until 80MHz. The signal injected is AM at 80%. The level is 20Vrms. Here is the setup ...
Dimitar Zhekov's user avatar
0 votes
0 answers
61 views

How can I calculate the coupling coefficient between two coils?

I have two planar, circular coils of different number of turns, inductances, and radius, stacked on top of each other. How can I calculate their coupling coefficient (k) based on their properties and ...
Theodor's user avatar
  • 65
2 votes
3 answers
144 views

If the impedance of two coils is measured to be identical at 250.0 kHz, is it safe to assume identical impedance across the spectrum?

This question pertains to matching two air-gap inductors for use in resonant coupling. Alternative solutions are welcomed and appreciated. The two coils shall be comprised of identical wire. The two ...
Aaron Butkovich's user avatar
5 votes
2 answers
1k views

AC coupling to center an oscillating waveform to 0V doesn't work

I have a simple sawtooth oscillating circuit that I would like to center to 0V (remove the DC component.) I have tried AC coupling but the output is still a little to high and not centered. Could ...
Charles Guilbault's user avatar
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0 answers
56 views

Impedance of antenna and noise propagation

I would like to better understand how noise is radiated. Suppose the circuit under study is a circuit with a DC/DC converter (source of noise) and an analog circuit (receiver) which is very sensible ...
Jess's user avatar
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1 answer
103 views

How should I interpret this circuit? [closed]

This circuit is a coupling relay circuit distributed. Looking at this circuit makes sense. Thank you for answer.
minminminmin's user avatar
2 votes
3 answers
823 views

Why don't WD NVMe SSDs have PCIe AC coupling capacitors?

I see no coupling capacitors on PCIE TX lanes. Is it Safe to Remove Coupling Capacitors? Or Is it possible to make capacitors into the chip? Add more photos:
Jue WANG's user avatar
6 votes
3 answers
2k views

Can I use a 250 nF instead of a 200 nF SMD ceramic capacitor?

Im trying to fix a broken GPU that has a missing 200 nF SMD ceramic capacitor. I found a similar one on a motherboard that has a capacitance of 250 nF. Is it possible to transfer it to fix the GPU? At ...
LuisCorner's user avatar
0 votes
0 answers
337 views

cross coupled nmos pair

For the given circuit, I am observing the source voltage of M1 and M2 as the min of the applied voltage. Here, the current is equal in both fets. But Vg is not the same. So, both cannot be in ...
prashanth's user avatar
  • 116
-1 votes
1 answer
84 views

Coupling 2 buck converter's output to increase output current

I'm quite new working with step-back converters, and I have to use them in the project I'm currently working. My board will have 24V/5A source input, and I want to step-down this tension to 12V, 5V ...
Kike Rueda's user avatar
0 votes
1 answer
646 views

Square wave distortion at low frequencies, high-pass filtering, AC coupling

This is an update on my previous question. As Hearth suggeste, I changed to DC coupling on my scope. This is what I got: That's a clear change. Not a perfect square waves but I guess it is because of ...
kawasaki997's user avatar
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0 answers
156 views

Optocoupler or DC/DC-converter for generation of trigger voltage

In my project I would like to trigger an external device with my electronic trigger system. The trigger voltage of the trigger system is 5 V, while the external device needs 24 V to be triggered. In ...
arc_lupus's user avatar
  • 724
4 votes
1 answer
193 views

How to properly couple DC in this biased headphone amplifier design on power-up?

I am a self-study noob to electronics (and audio electronics) but diligently learning every day :) Some things I understand well, others I'm fuzzy on. This device is a headphone amplifier using NE5532 ...
Gbps's user avatar
  • 145
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0 answers
248 views

Antenna inductance calculation (RFID applications, inductive coupling)

Inductance of various antenna coils of different shapes can be estimated. Some examples are: A circular coil with single turn. N turn multilayer circular coil. Spiral coil. N turn squae loop coil. ...
Ethz's user avatar
  • 1
3 votes
2 answers
362 views

Do high impedance nodes have higher noise due to inductive coupling as well?

This link clearly explains how high impedance nodes are susceptible to capacitive coupling noise. Is the same true for inductive coupling? As per my understanding, inductive coupling would induce an ...
Divya K.S's user avatar
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0 votes
0 answers
83 views

Filter for AC line coupling with audio signal source

I need a sharp notch filter (higher order) for the 50-60 Hz band, to be placed between AC 220/125 V power line and an audio source (not necessarily amplified), such that the input signal from the ...
FoSoFix's user avatar
0 votes
0 answers
125 views

Why am I getting a random offset voltage?

I have query about the following circuit which is an enable for a regulator. This is on a 2 layer PCB. OUT goes to a Schmidt Triggered Inverter to the clock on a D-Type Flip Flop, where the output ...
ronald_s56's user avatar
0 votes
1 answer
201 views

AC coupling of relay driving circuit - Driving relays using PWM

I have designed this circuit and math calculation works but looking back now I feel the cap is too small may be I am making any mistake here? Can some one explain how to chose the capacitor for AC ...
Power_Electronics's user avatar
19 votes
8 answers
3k views

What precisely is the numerical (or any) meaning of mutual inductance and, is it useful, representative (of something) or important?

When we consider two inductors that are magnetically coupled, we sometimes talk about mutual inductance. As an example, consider two inductors (such as 9 μH and 4 μH) that are 100% coupled and produce ...
Andy aka's user avatar
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1 vote
0 answers
190 views

Resonant Transformer / Resonant Inductive Coupling

I´m trying to build a resonant transformer (or a resonant inductive coupler, I don´t know if the names fit to the topology I´m showing, anyway). The idea is to develop a high voltage on a capacitor. ...
Lucas's user avatar
  • 11
0 votes
2 answers
87 views

LED on lamp outlet flashes when switch is off - is this capacitive coupling charging the power supply? And what to do about it? [closed]

I wanted to connect an LED light chain to a lamp outlet in my house in order to turn it on and off using the wall light switch. I have dismantled the 230V to 3V power supply that was built into the ...
UsernameError's user avatar
0 votes
0 answers
88 views

I’m working with pcf7991at antenna driver ic

Just wondering if you can help me I’m trying to calculate capacitor and resistor values for a 125khz inductor coil . My coil measures 6.8 ohms. I’m not sure how to calculate the capacitor values ...
Mjway's user avatar
  • 1
0 votes
1 answer
142 views

Headphone amplifier is humming

I have built headphone amplifier kit and connected it to the output of DVD player. It works but I can hear humming. The humming is present only when DVD is connected. There is no groundig of the boxes ...
azrael's user avatar
  • 1
8 votes
1 answer
1k views

Backwards compatibility of PCIe AC coupling capacitors

The PCIe base spec mentions that platforms operating only at 2.5GT/s or 5GT/s may use AC coupling capacitors in the 75nF-265nF and that platforms supporting 8GT/s and above must use 176nF-265nF. ...
user2005848's user avatar
1 vote
1 answer
577 views

Why there is capacitor in series in high speed designs like SGMII?

Why we are connecting capacitor in series in high speed designs like SGMII. If it is to remove DC voltages, why we are not using on other signals like I2C, SPI and so on. What is the major purpose. ...
Selva97's user avatar
  • 543
1 vote
1 answer
390 views

Can someone explain the dependence of coupling coefficient to inductance value to me? It seems counter intuitive

According to the formula \$K=M/\sqrt{L_1 L_2}\$, it seems that k is inversely proportional to the inductance values of the two coils. However, it seems to me that a coupling between two 2uH inductor ...
needbrainscratched's user avatar
0 votes
1 answer
265 views

How do terminate the coax shield of AC coupled LVDS signal? (isolated grounds)

I have an LVDS clock signal that goes to several PCB cards. Frequency: 100Hz --> 20MHz I am going to use a fan out IC to supply each card with it's own buffered CLK signal; I am not going do a '...
Tony's user avatar
  • 683
0 votes
1 answer
73 views

How to pass a signal over isolator with only one side powered?

I have a system composed of a 230VAC zone isolated from a human contact zone with a 7.5mm 2k5 space. On the human side there is a dry contact switch: I am searching for a less than 1€ solution to ...
Damezumari's user avatar
0 votes
0 answers
126 views

Coupled inductors formula

Suppose we have this circuit: simulate this circuit – Schematic created using CircuitLab According to the dot notation rule the current :The convention is that current entering a transformer at ...
Jun Seo-He's user avatar
2 votes
1 answer
218 views

Op-amp offset voltage and capacitive coupling

About the circuit above, I can't understand from the row "VA=2Vos". If that's because most of the voltage between 1K ohm resistor and capacitor is on 1K ohm then I can't understand why VA ...
Greenbanana's user avatar
0 votes
2 answers
463 views

Best way to connect coax along a microstrip

I have an open-ended (stripped, if needed) coaxial cable that I would like to use to insert a signal into a microstrip. The circuit (operating at ca. 18 GHz) however, is made in a way where I can't ...
nsnfn's user avatar
  • 13
1 vote
1 answer
184 views

Unkown DC offset of an isolation amplifier circuit design

I am designing an isolation amplifier that consists of the following blocks: A comparator which produces a PWM signal A coupling capacitor that achieves galvanic isolation A voltage follower that ...
Karol Warvic's user avatar
1 vote
0 answers
14 views

Coupled current in shield in a tube from a transient surge

If a shielded cable (B) is running inside the centre of a tubular structure (A), how is the coupled current from a surge estimated in the shield? I am trying to figure out how the coupled current ...
Kappel's user avatar
  • 11
0 votes
1 answer
191 views

Regarding Magnetic coupled circuit

Here, all the initial conditions are : i1(0-)=0A and i2(0-)=0A When t≥0, the current i1(t) and i2(t) starts flowing. From my assumption, steady state value of i1(t) is 10A but what happens to i2(t)? ...
Camila's voice's user avatar
0 votes
0 answers
122 views

Output AC coupling: upper limit or lower limit?

I bought a DC2900A board for my project. In its datasheet it is stated: The maximum repetition rate of the pulsed laser should be 100kHz. The DC2900A repetition rate is limited by the output AC ...
DD1's user avatar
  • 43
2 votes
0 answers
72 views

Why are the coupling capacitors needed in this DCM converter?

I have a 48V power supply which needs to be converted to a 12V output. I want to achieve this by using the DCM2322 dc/dc converter. In the Datasheet the following recommended circuit is given: My ...
Robbert Friendwijk's user avatar
1 vote
1 answer
285 views

Understanding of coupling coefficient and power transfer efficiency

I am a bit confused about my derivation to get power efficiency from the coupling coefficient. The coupling coefficient \$k=M/\sqrt{L_1L_2}\$. $$ V_2=M\frac{dI_1}{dt}=L_2\frac{dI_2}{dt}\\ V_1=M\frac{...
ONLYA's user avatar
  • 165
3 votes
2 answers
977 views

Location of AC coupling capacitors

I am trying to decide location of AC coupling capacitors between FPGA and PHY SGMII interface and datasheets of neither part has any useful information. I've read some notes, like this one from Dr. ...
sp2821's user avatar
  • 49
1 vote
2 answers
179 views

Oscilloscope probe coupling [duplicate]

I am using this buck converter. Schematic: Buck Converter Specifications : Input Voltage - 18V to 32V Switching Frequency - 300kHz Output Voltage 9V Load Current - 0mA to 200mA Maximum. When ...
user avatar
3 votes
5 answers
1k views

Roles of the coupling and bypass capacitors in a CE transistor

I wonder what the purpose of the coupling capacitors and the bypass capacitors are and the type of effect each capacitor has on the circuit. As I've understood it, you use coupling capacitors to block ...
gripen's user avatar
  • 63
0 votes
2 answers
84 views

What is the right way to measure K on an inductor with three coils?

I have an inductor which has three coils, L1, L2, L3. In normal use L2 and L3 are connected in series, and resonated with a capacitor. L1 would then drive the tank circuit. In Spice, I need the ...
user103218's user avatar
1 vote
1 answer
70 views

How is this LCD controlled?

Source: https://ozhealth.com.sg/product/genial-digital-thermometer-t15-orange/ I tore down a digital thermometer today (a Genial T15), and the interface to the LCD caught my eye: although there were ...
built1n's user avatar
  • 113
0 votes
1 answer
249 views

Why isn't capacitive coupling considered in EMC testing?

It seems like the emissions of interest in EMC testing are radiated and conducted emissions. Is this because capacitive coupling is so weak it doesn't pose a threat to other devices?
zsky3333's user avatar
  • 489
1 vote
3 answers
1k views

DC-DC converter isolation capacitance return path?

For those isolated DC-DC converter bricks like seen in the photo below: The data sheet specifies an isolation capacitance in the order of picofarads. And in order to meet EMC requirements they ...
zsky3333's user avatar
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