Inductors, coils and chokes are passive devices that are designed to resist changes in current and store energy in the form of a magnetic field. In their simplest form, inductors consist of a wire loop or coil. The inductance is directly proportional to the number of turns in the coil.   Inductance also depends on the radius of the coil and on the type of material around which the coil is wound. With inductors, coils and chokes, air cores result in the least inductance for a...
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Q & A on Inductors, Coils, and Chokes

We asked our users for their input on Inductors, Coils, and Chokes. Here are the results of 93 users familiar with Inductors, Coils, and Chokes.

Who Took Our Poll? | Design Trends | Applications and Use | Features | Buying Advice |

Who Took Our Poll?Top

Design TrendsTop

Q:
What new technologies are influencing inductor, coil and choke design?
15 answers
Answers:
Need to avoid THT parts (talking about power inductors, more then 5 Amps)
~Riccardo D, Design Engineer, Brescia, Italy
Small compact SMD components. New Ferrite & other materials.
~Rai R, Engineering Consultant, New Delhi, INDIA
Surface mount technology - as opposed to previous thru-hole.
~Robert C, Retired engineer, Roland, OK
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Q:
From your perspective, which companies are creating the most innovative inductors, coils and chokes?
14 answers
Answers:
I don't know, I gave up looking when I couldn't find a 7 microhenry to 7 microhenry transformer, which would have been advantageous to my musical instrument.
~James Falk, Purchaser, Scottsdale, AZ
I've seen several on your web site lately that were impressive.
~Robert C, Retired engineer, Roland, OK
Vishay and Wurth are quite good..
~Engineer, Rødkærsbro, Denmark
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Applications and UseTop

Q:
What are some of the applications you have used inductors, coils and chokes for?
32 answers
Answers:
RF-filter, divide electronics in smaller parts to suppress radiation, separate electronics from wires by use of self resonance in common mode choke, convert unbalanced signals to balanced signals by use of common mode choke.
~Christian Nielsen, EMC specialist, Copenhagen, Denmark
1) Used in low voltage AC/DC Adopters. 2) Used in Audio Circuits. 3) Used in Hi Fi Speaker systems. 4)Used in RF Amplifiers. 5) Used in UPS & Inverters. 6) Used in Signal Mixing & Filtering. And a lot more.
~Rai R, Engineering Consultant, New Delhi, INDIA
Noise protection, oscillators, pulse shaping, tuned circuits, timing circuits, linear waveforms, ferrite beads, high voltage, etc.
~Robert C, Retired engineer, Roland, OK
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Q:
Please share with us any “non-standard” applications that inductors, coils and chokes have been used for.
8 answers
Answers:
In what would not be recognized, they could be thought of as the series of sensors that measure both the electric & magnetic fields from nuclear weapon explosions, both real & simulated as we tested, various war planes, the Minuteman fleet silos for penetration (& survival) of EMP,, ElectroMagnetic Pulse. The measurements of nuclear bomb tests in NTS use 6 inch air-nitrogen filled co-ax cables that must be carefully compensated with inductors (chokes) etc to handle the alpha signals to the 6 GHz oscilloscopes -- etc.
~Robert C, Retired engineer, Roland, OK
Inductors go from microhenries on up through henries. Capacitors go from microfarads on up to farads...they can actually be used to generate audio frequencies that can thereby be amplified with a transistor amplifier and reverbed through an op amp.
~James Falk, Purchaser, Scottsdale, AZ
I think all applications are Standard until we have used for them.
~Rai R, Engineering Consultant, New Delhi, INDIA
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Q:
Do you know of any disastrous mistakes that occurred due to the incorrect usage of inductors, coils and chokes?
4 answers
Answers:
Typical error is saturation, which results in overheating, progressive deterioration of coil insulation & eventual failure in many circuits. Poor design, poor reliability, short MTBF.
~Robert C, Retired engineer, Roland, OK
A large coil in front of a SMPS can easily give some instability problems, so a workaround has to be made.
~Engineer, Rødkærsbro, Denmark
Selection of replacement or x-ref parts made by purchase office, without asking the technical office.
~Riccardo D, Design Engineer, Brescia, Italy

FeaturesTop

Q:
What would your design or feature "wish list" be for this product?
12 answers
Answers:
GlobalSpec should database all the different catalogs together instead of me having to sign into each one. Perhaps open source the idea too so that each part can be cadded (perhaps via freeware), and then people could start making instant royalties off of building an e-kit out of the cadded parts on the master database.
~James Falk, Purchaser, Scottsdale, AZ
Core with low magnetic radiation. Magnetically shielded. Broad frequency range 0 - 2.5GHz. Low DC resistance. Size 0402 or smaller.
~Christian Nielsen, EMC specialist, Copenhagen, Denmark
Improvements in core materials, ( B-H curve ) more efficient, higher flux density per weight of core ( "steel" ).
~Robert C, Retired engineer, Roland, OK
Better datasheets would be nice. Difficult to design SMPS when you do not know the loss at higher frequencies.
~Engineer, Rødkærsbro, Denmark
1.Compact Inductors for high current applications
~MURALIDHAR MEDA, Project Manager, BANGALORE, India
Comprehensive, clear and fast to use selection charts.
~Riccardo D, Design Engineer, Brescia, Italy
Less weight, smaller size, easy connection
~Project Manager, Istanbul, Turkey
Extremely low DCR to minimize Power loss.
~Rai R, Engineering Consultant, New Delhi, INDIA
Inductance, rated current, smaller size
~Ben T, Design Engineer, Shenzhen, China
Small and Inexpensive with less steel
~Marketing/Sales, Indianapolis, IN
Tolerance should be very low
~Engineering, Faculty/Staff/Student, Gadag, India
Rf coils smd
~Mario Cisilino, Research & Development, BSAS Argentina, Argentina

Buying AdviceTop

Q:
Do you have any advice for people relative to buying or using inductors, coils and chokes?
4 answers
Answers:
"Magnetics", magnetic phenomenon is not well understood by many -- indeed, many that should understand it. There are more things that must be known to use these things well, not just Om's Law.
~Robert C, Retired engineer, Roland, OK
Now days most commonly the inductors are available for any application, we need not take pains to design these inductors except for few instances where we need to design the inductors.
~MURALIDHAR MEDA, Project Manager, BANGALORE, India
Select as per the specific requirement & from standard / Trusted Suppliers.
~Rai R, Engineering Consultant, New Delhi, INDIA
Yes, read the data sheet very well
~Mario Cisilino, Research & Development, BSAS Argentina, Argentina

Q:
Is there any advice you want to share with users to help them avoid common errors in selection or usage of inductors, coils and chokes?
4 answers
Answers:
Must see the magnetic properties of Stamping Core material & Ferrite composition.
~Rai R, Engineering Consultant, New Delhi, INDIA
Be aware of multiple filtering inductors placed side-by-side in your layout.
~Riccardo D, Design Engineer, Brescia, Italy
Read very well the values when the coils are with colors code.
~Mario Cisilino, Research & Development, BSAS Argentina, Argentina
Understand the B-H curve, & ferrites in general.
~Robert C, Retired engineer, Roland, OK


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