Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [choke]

Anything related to choke inductors, i.e. inductors designed or used for the specific purpose of blocking an AC signal from reaching a part of a circuit, while letting the DC component (or lower frequency components) to pass undisturbed.

Anything related to choke inductors, i.e. inductors designed or used for the specific purpose of blocking an AC signal from reaching a part of a circuit, while letting the DC component (or lower frequency components) to pass undisturbed.

See also Wikipedia on electronic chokes.

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Are Common Mode Choke Coils needed on USB?

I was looking over the schematic for the GumStix Palo 43 and noticed they used a common mode choke coil on the data lines coming in from USB. I understand how this design can help remove noise coming in on the USB lines, but I wonder if it is…
Kellenjb
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What's the purpose of crossing over in the middle of a toroid winding?

Seeing toroids wound like this is somewhat common in the amateur radio hobby to reduce common-mode current on an antenna feedline: Why the cross over the middle? As far as I can tell, all the turns go around the core in the same direction. Why not…
Phil Frost
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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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Smoothing a High Current PWM

I am using a MOSFET to control the average voltage to a device by varying the duty cycle to the base as shown in the diagram below. My question is what is the best circuit to use in the "filter box" in order to "smooth" the PWM into its analogue…
Anthony Phan
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Trifilar Transformer Common-Mode Rejection Circuit (Signal Recovery, Hybrid Combiner, RF)

I'm trying to develop a circuit that allows me to effectively subtract two different sources of RF noise from a single signal at the same time. I am planning to use something called a "trifilar" transformer, which is effectively a transformer with…
iwantmyphd
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How are air-core inductors typically constructed?

I'm considering learning to build air-core inductors for power applications. For example, I presently want a .5-1 mH choke capable of handling 50 amps for two seconds. Winding my own air-core seems like it might be a cost-effective solution, but…
Stephen Collings
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sizing a DC bias RF choke for a differential antenna + PA

Trying to figure an antenna for the Si4012 RF chip. Page 26 of https://www.silabs.com/documents/public/application-notes/AN639.pdf talks about feeding the two sides of the loop antenna through two pull-up inductors (LP and LM) which it fails to…
kellogs
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Is there a difference between a choke, a reactor, and an inductor?

I've seen all three of these terms used interchangeably. But once when I did so, I was told I was using one of the terms incorrectly. Are these terms, in fact, equivalent? Or are there differences between them?
Stephen Collings
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How can I determine the voltage insulation rating of magnet wire?

As an extension of my previous inquiry into air-core chokes, I'm trying to determine the voltage insulation rating of magnet wire, without much luck. Few of the audio air-core choke manufacturers list that data, and none of the magnet wire…
Stephen Collings
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Are there any unexpected effects when printing an inductor on a PCB?

Suppose I print an eight-layer PCB, with a spiral starting on the top layer and continuing through all the inner layers to the bottom. Assuming I keep the spiral turning in the same direction on all layers, this PCB should act as an inductor. (I…
Stephen Collings
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Using LC filter instead of RC filter in mains powered circuits

Above is a dimmer circuit. In some of these circuits I see a toroid inductor together with a capacitor forming a low pass LC filter which is called choke filter. My questions are: Why is RL used instead of RC and is that something to do with the…
user16307
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Why does a cap in front of a choke input suply reduce rectifier current? How to calculate optimal value?

As I was designing the power supply for my tube amp, I was trying to reduce the negative transients of the choke input supply, I tried to add a capacitor in front of it (C1 in the schematic). It reduced the transients, but also reduced the peak…
Pentium100
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Why do receivers have a choke but transmitters don't?

Here's a receiver I found on the web: And here's a transmitter: [ Why do receivers have an inductor specifically designated as a choke (RFC) in their circuits but transmitters don't?
user116345
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Can a CM choke be used to suppress common mode current in a DC circuit?

I have a setup with a DC/DC converter like in the figure below. I need to minimize common mode current on the supply input. There are no other connections besides Vsupply + and - and Rload + and -. I'm in doubt whether a CM choke will help…
MrPiet
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Are ferrite beads supposed to be magnetic?

I have replaced the ferrite bead on my audio cable with new ones that I just bought. But I have tested them and they aren't magnetic, it's just like a cylindric metal inside it, but I thought it has to be magnetic to perform it's task. Does the…
jack79
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