Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [common-mode-choke]

A type of choke in which two coils are wound on a single core in order to pass differential currents while blocking common mode currents.

A type of choke in which two coils are wound on a single core in order to pass differential currents while blocking common mode currents. See Wikipedia's information about common mode chokes.

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Ferrite bead vs common mode choke

simulate this circuit – Schematic created using CircuitLab I inherited the top circuit from a previous designer on my robotics team. The circuit uses two ferrite beads, a zener, a TVS and a capacitor to filter incoming power. The incoming power…
vini_i
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What exactly happens to the signals hitting a common mode choke?

I'm trying to better understand the principles behind the common mode choke. I made a few drawings to clarify.   Differential Mode Signals Differential currents (driven by differential voltages) create equal but opposite magnetic fields B in the…
K.Mulier
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Why does this isolation transformer have another transformer in it?

The isolation transformer I'm looking at: http://www.mouser.com/ds/2/336/HX1188NL-515471.pdf My question is why is it there? Is it not enough to have just the transformer on the left?
VanGo
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Why are the transformer windings in series with line and load in this circuit?

I came across this switching power supply circuit and I noticed the transformer is connected in a way I had never seen before. What is the benefit of connecting it like that? And why does the circuit use a capacitor voltage divider?
Gabriel Góes Rodrigues
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Can I use a common mode choke as a coupled inductor in a SEPIC converter

I do not really understand the difference between common mode chokes and coupled inductors. They are both 2 coils wrap around the same core but I know they have different purposes. I want to design a SEPIC converter with a coupled inductor but it…
Sonia
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Common mode choke - symbol and orientation

I was wondering why there are different symbols for common mode chokes and if/how they affect the way I have to connect them. (Upper image is incorrect but left here for understanding the comment from @Felthry) Most often I see type 1 and there is…
Peder
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How can I model this common mode choke in circuit in LTspice?

How can the common mode choke in below diagram used in LTspice? By an inductor or transformer? How should be the circuit drawn in LTspice? I want to use this to filter out CM noises for single ended coaxial cable.
floppy380
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How to use common mode choke inductors? (differential vs common mode)

I have yet to undestrand exactly how to use common mode chokes inductors, according to the datasheet they have 2 operation modes like in the picture common mode and differential mode, however im afraid i dont understand the datasheet itself As you…
GoatZero
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How to check the polarity of a common-mode choke?

I purchased some common-mode chokes and the documentation provided states: As this pinout does not correspond to other chokes of the same format, I have doubts about the position of the dots (pins 1 and 3). So I tried to measure the values of the…
Nikita
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PCB Layout - Common Mode Choke

Why it is recommended to not to add copper planes and to avoid routing of signals under the common mode chokes?
ChandanN
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How to eliminate noise from switched power supply

I have an isolated switching power supply (120v in, 12v out) that gives an output shown in Figure 1 when referenced to the output ground (I'm not TOO worried about that noise). The bigger issue I have is the noise I have when referencing the output…
Tyler Fontaine
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Why are common mode chokes with 90 ohm @ 100 MHz recommended for USB 2.0 Hi-Speed data lines?

When one looks at common mode chokes for USB 2.0 applications choke manufacturers always recommend CMC with a common mode impedance of 90 ohms @ 100 MHz. Example How does this relate to USB 2.0 differential impedance of 90 ohms (& 45 ohm single…
CatastrophicFailure
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How to design a CMC (Common Mode Choke) footprint to allow no-pop solution

How would you design in CMC's with a 0504 (1210 metric) 4-lead package to allow for a no populate (do not pop, DNP,DNI) solution? I am thinking 0402 0ohm (zero ohm) resistor but cannot picture the PCB layout? Specifically, this is for USB data…
RuggedEngie
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Common mode choke in circuit with multiple ground connections

I'm designing an automotive circuit where I'm using a reference power design from TI. Together with protection circuitry, this design includes a common mode choke. The same circuit has an antenna input, and this antenna is grounded to the car…
JohnDonut
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Measuring / estimating unknown common mode choke and transformer

Out of curiosity and to improve my reverse-engineering skills, I'm currently reverse engineering a rather simple 12V switch-mode power supply adapter. Most of the markings and the topologies are fine, except two components: the common-mode…
polemon
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