Author Topic: Air cored inductors proximity to conductive objects  (Read 1141 times)

Offline John123

  • High Voltage Engineer
  • ****
  • Posts: 238
  • Karma: +5/-0
  • All the gear, no idea. UK
    • View Profile
Air cored inductors proximity to conductive objects
« on: November 23, 2022, 01:10:17 AM »
Can air cored inductors be influenced by proximity to other conductive things such as heatsinks even if nothing actually enters the inside of the windings? I'm talking about simple ones such as this:

Offline davekni

  • Executive Board Member
  • *******
  • Posts: 2680
  • Karma: +127/-1
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: Air cored inductors proximity to conductive objects
« Reply #1 on: November 23, 2022, 04:44:20 AM »
Quote
Can air cored inductors be influenced by proximity to other conductive things such as heatsinks even if nothing actually enters the inside of the windings? I'm talking about simple ones such as this:
Yes, but much less so than similar ferrite-core inductors.  With air-core, most of the magnetic reluctance is where field is concentrated through core center.  With lots of area for field to return outside of the coil, blocking some of that return path has only a tiny effect.  Unless you block much of it, such as if you milled a slot in a heatsink and placed it over the coil blocking most field return paths.
David Knierim

Offline Twospoons

  • High Voltage Engineer
  • ****
  • Posts: 214
  • Karma: +5/-0
    • View Profile
Re: Air cored inductors proximity to conductive objects
« Reply #2 on: November 23, 2022, 09:29:01 AM »
It would be very dependent on the aspect ratio of the coil - long skinny vs wide flat.  This is how basic metal detectors work, after all, by using a wide flat coil.

Offline John123

  • High Voltage Engineer
  • ****
  • Posts: 238
  • Karma: +5/-0
  • All the gear, no idea. UK
    • View Profile
Re: Air cored inductors proximity to conductive objects
« Reply #3 on: November 23, 2022, 11:27:18 PM »
Quote
Can air cored inductors be influenced by proximity to other conductive things such as heatsinks even if nothing actually enters the inside of the windings? I'm talking about simple ones such as this:
Yes, but much less so than similar ferrite-core inductors.  With air-core, most of the magnetic reluctance is where field is concentrated through core center.  With lots of area for field to return outside of the coil, blocking some of that return path has only a tiny effect.  Unless you block much of it, such as if you milled a slot in a heatsink and placed it over the coil blocking most field return paths.
Thanks Dave, here's some photos of it. Excuse the messy amateur DIY construction.


It would be very dependent on the aspect ratio of the coil - long skinny vs wide flat.  This is how basic metal detectors work, after all, by using a wide flat coil.
It's a single layer coil measuring 32.5mm x 15mm and about 26 turns of litz wire (was aiming for a couple uH). It's 12mm at its closest point from the grounded heatsink. Flying blue wire is circuit ground.
« Last Edit: November 23, 2022, 11:30:29 PM by John123 »

Offline davekni

  • Executive Board Member
  • *******
  • Posts: 2680
  • Karma: +127/-1
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: Air cored inductors proximity to conductive objects
« Reply #4 on: November 24, 2022, 03:02:11 AM »
Looks fine.  Heat sink should have negligible effect on inductance of coil with that geometry.
David Knierim

High Voltage Forum

Re: Air cored inductors proximity to conductive objects
« Reply #4 on: November 24, 2022, 03:02:11 AM »

 


* Recent Topics and Posts

post Re: DIY X-RAY generator made of eBay parts
[X-ray]
PhotonLab
February 20, 2024, 03:14:58 PM
post Re: DIY X-RAY generator made of eBay parts
[X-ray]
alan sailer
February 19, 2024, 06:08:05 PM
post Re: Ramped DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
February 19, 2024, 03:03:37 PM
post Re: ZCS for SSTC without E class??
[Solid State Tesla Coils (SSTC)]
AstRii
February 19, 2024, 04:34:22 AM
post Re: ZCS for SSTC without E class??
[Solid State Tesla Coils (SSTC)]
davekni
February 19, 2024, 04:27:28 AM
post Re: ZCS for SSTC without E class??
[Solid State Tesla Coils (SSTC)]
AstRii
February 19, 2024, 03:59:51 AM
post Re: ZCS for SSTC without E class??
[Solid State Tesla Coils (SSTC)]
davekni
February 19, 2024, 03:45:51 AM
post Re: Ramped DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
February 19, 2024, 03:30:09 AM
post Re: ZCS for SSTC without E class??
[Solid State Tesla Coils (SSTC)]
AstRii
February 19, 2024, 02:38:49 AM
post Re: Ramped DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
February 19, 2024, 01:52:20 AM
post Re: Lathe Restauration
[General Chat]
TMaxElectronics
February 19, 2024, 12:47:27 AM
post Re: VS-GP250SA60S IGBT suitability - no flywheel diode
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
February 18, 2024, 10:32:36 PM
post Re: Ramped DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
February 18, 2024, 10:06:58 PM
post Re: VS-GP250SA60S IGBT suitability - no flywheel diode
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hydron
February 18, 2024, 11:43:44 AM
post Re: VS-GP250SA60S IGBT suitability - no flywheel diode
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Keybored
February 18, 2024, 03:41:12 AM
post Re: Ramped DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
February 18, 2024, 02:43:37 AM
post Re: Ramped DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
February 17, 2024, 10:45:17 PM
post Re: Ramped DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
February 17, 2024, 10:29:30 PM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
February 17, 2024, 10:20:39 PM
post Re: Ramped DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
February 17, 2024, 10:14:20 PM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
February 17, 2024, 08:56:42 PM
post Re: Ramped DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
February 17, 2024, 08:52:45 PM
post Re: DIY X-RAY generator made of eBay parts
[X-ray]
PhotonLab
February 16, 2024, 09:20:44 AM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
February 16, 2024, 03:50:58 AM
post Re: Ramped DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
February 16, 2024, 03:27:18 AM
post Re: DIY X-RAY generator made of eBay parts
[X-ray]
klugesmith
February 16, 2024, 01:55:48 AM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
February 15, 2024, 07:11:20 PM
post Re: DIY X-RAY generator made of eBay parts
[X-ray]
PhotonLab
February 15, 2024, 11:31:42 AM
post Re: ZCS for SSTC without E class??
[Solid State Tesla Coils (SSTC)]
davekni
February 15, 2024, 06:01:49 AM
post Re: ZCS for SSTC without E class??
[Solid State Tesla Coils (SSTC)]
AstRii
February 15, 2024, 05:13:13 AM
post Re: ZCS for SSTC without E class??
[Solid State Tesla Coils (SSTC)]
davekni
February 15, 2024, 04:26:00 AM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
February 14, 2024, 06:25:45 PM
post Re: DIY X-RAY generator made of eBay parts
[X-ray]
Luca c.
February 14, 2024, 03:33:25 PM
post Re: ZCS for SSTC without E class??
[Solid State Tesla Coils (SSTC)]
AstRii
February 14, 2024, 12:57:01 PM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
February 14, 2024, 05:32:30 AM
post Re: ZCS for SSTC without E class??
[Solid State Tesla Coils (SSTC)]
davekni
February 14, 2024, 05:22:35 AM
post Re: VS-GP250SA60S IGBT suitability - no flywheel diode
[Dual Resonant Solid State Tesla coils (DRSSTC)]
AstRii
February 14, 2024, 04:34:14 AM
post Re: VS-GP250SA60S IGBT suitability - no flywheel diode
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Keybored
February 14, 2024, 03:02:16 AM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
February 14, 2024, 01:58:17 AM
post Re: ZCS for SSTC without E class??
[Solid State Tesla Coils (SSTC)]
AstRii
February 13, 2024, 09:30:40 PM
post DIY X-RAY generator made of eBay parts
[X-ray]
PhotonLab
February 13, 2024, 03:54:23 PM
post VS-GP250SA60S IGBT suitability - no flywheel diode
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Keybored
February 13, 2024, 09:57:12 AM
post Re: TNY265 flyback issue
[Transformer (Ferrite Core)]
davekni
February 13, 2024, 03:50:05 AM
post Re: TNY265 flyback issue
[Transformer (Ferrite Core)]
AstRii
February 12, 2024, 07:30:42 PM
post Re: PLL "IHFSSTC" concept and schematic
[Solid State Tesla Coils (SSTC)]
Anders Mikkelsen
February 11, 2024, 10:30:38 PM
post Re: Help finding correct IGBT Module
[General Chat]
rikkitikkitavi
February 11, 2024, 09:41:57 PM
post Re: PLL "IHFSSTC" concept and schematic
[Solid State Tesla Coils (SSTC)]
Lucasww
February 11, 2024, 06:34:35 AM
post Re: TNY265 flyback issue
[Transformer (Ferrite Core)]
davekni
February 10, 2024, 03:55:35 AM
post Help finding correct IGBT Module
[General Chat]
cnichols
February 09, 2024, 09:34:13 PM
post TNY265 flyback issue
[Transformer (Ferrite Core)]
AstRii
February 09, 2024, 06:45:46 PM
post Re: Help Sourcing or Debugging My Small HV Module
[Transformer (Ferrite Core)]
michaelrcolton
February 08, 2024, 07:04:07 PM
post ESAB Bantam TBH 140 Welder Restoration
[Laboratories, Equipment and Tools]
Mads Barnkob
February 08, 2024, 06:47:35 PM
post Re: Anyone used iCCFL.com?
[Transformer (Ferrite Core)]
FPS
February 08, 2024, 12:27:47 AM
post Re: PLL "IHFSSTC" concept and schematic
[Solid State Tesla Coils (SSTC)]
Anders Mikkelsen
February 07, 2024, 09:49:11 PM
post Re: Anyone know of a good variable driver?
[Beginners]
NyaaX_X
February 07, 2024, 04:48:02 PM
post Re: Anyone know of a good variable driver?
[Beginners]
FPS
February 07, 2024, 08:17:37 AM
post Re: How much power?
[Spark Gap Tesla Coils (SGTC)]
Terry
February 06, 2024, 10:51:35 PM
post Re: OCXO Reference devolopment - or a story about scaleability
[Radio Frequency]
Mads Barnkob
February 06, 2024, 07:29:29 PM
post Re: Anyone used iCCFL.com?
[Transformer (Ferrite Core)]
MRMILSTAR
February 05, 2024, 05:18:33 AM
post Re: Anyone know of a good variable driver?
[Beginners]
Mads Barnkob
February 04, 2024, 09:16:25 PM
post Re: PLL "IHFSSTC" concept and schematic
[Solid State Tesla Coils (SSTC)]
davekni
February 04, 2024, 09:13:36 PM
post Anyone used iCCFL.com?
[Transformer (Ferrite Core)]
FPS
February 04, 2024, 09:00:30 PM
post Re: Anyone know of a good variable driver?
[Beginners]
FPS
February 04, 2024, 08:56:14 PM
post Re: OCXO Reference devolopment - or a story about scaleability
[Radio Frequency]
Da_Stier
February 04, 2024, 08:18:01 PM
post Re: Anyone know of a good variable driver?
[Beginners]
Mads Barnkob
February 04, 2024, 08:04:36 PM
post OCXO Reference devolopment - or a story about scaleability
[Radio Frequency]
Da_Stier
February 04, 2024, 07:56:55 PM
post Re: PLL "IHFSSTC" concept and schematic
[Solid State Tesla Coils (SSTC)]
Lucasww
February 04, 2024, 08:45:53 AM
post Anyone know of a good variable driver?
[Beginners]
FPS
February 04, 2024, 12:56:52 AM
post Re: looking for a pll sstc schematic with gate driver ic.
[Solid State Tesla Coils (SSTC)]
yourboi
February 03, 2024, 07:01:12 PM
post Re: SSTC bus inductance
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
February 03, 2024, 08:04:29 AM
post Re: SSTC bus inductance
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
February 03, 2024, 06:01:12 AM
post Re: is there a standard pinout of optical audio output connectors?
[Electronic Circuits]
Rafft
February 02, 2024, 05:04:44 PM
post SSTC bus inductance
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
February 02, 2024, 08:34:56 AM
post Re: How much power?
[Spark Gap Tesla Coils (SGTC)]
klugesmith
February 01, 2024, 07:03:41 PM
post Does anyone have a 3d print form for a spiral primary on 4" pvc?
[Solid State Tesla Coils (SSTC)]
yourboi
February 01, 2024, 06:23:45 PM
post Re: How much power?
[Spark Gap Tesla Coils (SGTC)]
Mads Barnkob
February 01, 2024, 07:53:53 AM
post Re: How much power?
[Spark Gap Tesla Coils (SGTC)]
klugesmith
January 31, 2024, 11:43:32 PM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
Ranni81
January 31, 2024, 08:03:40 PM
post Re: How much power?
[Spark Gap Tesla Coils (SGTC)]
Hysteresis
January 31, 2024, 03:34:48 PM
post Re: How much power?
[Spark Gap Tesla Coils (SGTC)]
MRMILSTAR
January 31, 2024, 05:08:10 AM
post Re: How much power?
[Spark Gap Tesla Coils (SGTC)]
Mads Barnkob
January 30, 2024, 10:17:45 PM
post How much power?
[Spark Gap Tesla Coils (SGTC)]
Terry
January 30, 2024, 08:07:39 PM
post Ultrasonic Plastic Welding experiments with TA-40CS transducer
[Transformer (Ferrite Core)]
davekni
January 28, 2024, 11:37:30 PM
post Re: is there a standard pinout of optical audio output connectors?
[Electronic Circuits]
yourboi
January 28, 2024, 03:07:12 AM
post Re: First time DRSSTC Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Saattvik24
January 27, 2024, 02:27:29 PM
post Re: Lathe Restauration
[General Chat]
Mads Barnkob
January 27, 2024, 01:26:34 PM
post Re: Determine output voltage of DRSSTC
[General Chat]
Mads Barnkob
January 27, 2024, 01:15:51 PM
post Re: is there a standard pinout of optical audio output connectors?
[Electronic Circuits]
Mads Barnkob
January 27, 2024, 01:13:29 PM
post Determine output voltage of DRSSTC
[General Chat]
Pavol
January 27, 2024, 11:35:35 AM
post is there a standard pinout of optical audio output connectors?
[Electronic Circuits]
yourboi
January 27, 2024, 01:47:13 AM
post Re: First time DRSSTC Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
AstRii
January 26, 2024, 11:26:11 PM
post Re: First time DRSSTC Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Saattvik24
January 26, 2024, 08:24:30 PM
post Re: Next Gen DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Netzpfuscher
January 26, 2024, 05:19:18 PM
post Re: Anyone had success using analogue/digital HV panel meters?
[Beginners]
MRMILSTAR
January 26, 2024, 04:28:38 PM
post Re: Anyone had success using analogue/digital HV panel meters?
[Beginners]
Luca c.
January 26, 2024, 03:34:10 PM
post Re: Anyone had success using analogue/digital HV panel meters?
[Beginners]
FPS
January 26, 2024, 11:49:48 AM
post Re: Anyone had success using analogue/digital HV panel meters?
[Beginners]
TizianoBll
January 26, 2024, 11:04:37 AM
post Re: Next Gen DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
January 26, 2024, 06:26:58 AM
post Anyone had success using analogue/digital HV panel meters?
[Beginners]
FPS
January 26, 2024, 06:25:52 AM
post Re: First time DRSSTC Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Manz
January 25, 2024, 06:06:49 PM

Sitemap 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
SimplePortal 2.3.6 © 2008-2014, SimplePortal