Questions tagged [coupling]
172 questions
38
votes
3 answers
Can people act like antennas?
I was watching my oscilloscope as I was holding a very short wire attached to the probe. It was showing about 0 voltage (small spikes) until I touched the metal. When I touched the metal, the scope immediately showed a 60.0Hz (peroid of 16.66ms),…
dpdt
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23
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What is the difference between a transformer and a coupled inductor?
Transformers and coupled inductors seem very similar. Is there a difference in construction? Or only in use?
This question asks something similar, but the answers don't address my question:
Coupled inductor vs an actual transformer?
Stephen Collings
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19
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8 answers
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 magnetic fields that are aiding. We calculate…
Andy aka
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11
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2 answers
DC/AC coupling in an oscilloscope
When using an oscilloscope, when is it (in general) better to use DC coupling over AC coupling and vice versa?
Vetenskap
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11
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2 answers
How do I size the coupling capacitance for a SEPIC converter?
The app notes I've seen for a SEPIC converter1 all tell me to size the coupling capacitor for ripple currents and voltages. I haven't seen one that tells me how to size the capacitance. Obviously there's some minimum; zero capacitance means no…
Stephen Collings
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9
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2 answers
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 grid and measures voltage and current (in theory, it…
nemewsys
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8
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1 answer
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.
However, PCIe uses low frequency pulses to detect the…
user2005848
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8
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4 answers
Why is a resistor added after the DC blocking capacitor of the op-amp input?
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 this problem?
Shivam suhane
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8
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4 answers
How to know exact Decoupling Capacitor values for supply voltages?
When designing circuits using various components such as IC's a lot of the time the data sheets give you an example schematic where they will usually give you some values for decoupling Capacitors. I usually see a 0.1 uF cap in parallel with a 10 uF…
Aaru
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7
votes
2 answers
How do I determine safe distance from a choke to prevent accidental coupling?
In most of my power converter applications, I end up with a choke of some description, somewhere in a steel chassis. I have seen and heard tell of situations where the choke couples to the steel of the chassis. In some cases, the windings heat up…
Stephen Collings
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6
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3 answers
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 first if thought the capacitors were 220 nF…
LuisCorner
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6
votes
2 answers
Electric shock from laptop due to capacitive coupling?
If a person touches an exposed wire (the wire has a ground-prong) on the 20V side of a power cable while barefoot, I heard that it is possible to receive a shock of higher than 20V due to capacitive coupling. Could anyone explain how this is…
minusatwelfth
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5
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2 answers
AC coupled gate drive
I am trying to get a MOSFET/IGBT driver to work for almost a year. The last efforts utilizing a bipolar Totem pole driver failed without mercy.
For some time I studied alternatives and came to AC coupled gate drive by Laszlo Balogh. (edit: see p.28…
jon ardaron
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5
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1 answer
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 capacitors based on the device's circumstances.
To…
Sepehr
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5
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4 answers
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 if it's too far apart (not a physicist, this may…
Whelchel
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