Measuring coil inductance

[dbanner]

Look at this video:

https://www.youtube.com/watch?v=Ff5xOENID7w

Then go here:

https://www.robkalmeijer.nl/techniek/electronica/radiotechniek/hambladen/73/1990/09/page48/index.html

[kt315]

try this

[kt315]

L adapter

[Nandor]

Nice topic That guy has many other interesting videos.

[bbsailor]

Math trick to use when measuring inductance

If you wind a coil with 19 turns and it measures 310 uH, what is the coil value if you added another turn? Here is the simple math trick using a common calculator. With a 20 turn coil you just added one turn. Divide 20 by 19 and get 1.05263 on your calculator. Now just square that number and get 1.108. Now just multiply 310 uH by this amount and get 343.48 uH for a 20 turn coil. This measurement takes into account the measured inductance of your shorter coil with the wire type, insulation dielectric constant and insulation thickness. This method shows how a coil value is based on the square of the turns difference. Double the turns and the coil value is now 4 times higher. I am just putting theory into a practical use. I hope this helps.

Joseph J. Rogowski

[Carl-NC]

Math trick to use when measuring inductance

If you wind a coil with 19 turns and it measures 310 uH, what is the coil value if you added another turn? Here is the simple math trick using a common calculator. With a 20 turn coil you just added one turn. Divide 20 by 19 and get 1.05263 on your calculator. Now just square that number and get 1.108. Now just multiply 310 uH by this amount and get 343.48 uH for a 20 turn coil. This measurement takes into account the measured inductance of your shorter coil with the wire type, insulation dielectric constant and insulation thickness. This method shows how a coil value is based on the square of the turns difference. Double the turns and the coil value is now 4 times higher. I am just putting theory into a practical use. I hope this helps.

Joseph J. Rogowski

This is a rough rule-of-thumb that varies with total turns and insulation thickness. In one set of coils I wound with 24awg PVC-insulated wire, the actual ratio was (0.991*N1/N2)^1.87. But (N1/N2)^2 will get you in the ballpark.

[Qiaozhi]

Or simply use the Coil Calculator
which is now celebrating 10 years of use in the Geotech forums.

[kt315]

Or simply use the Coil Calculator
which is now celebrating 10 years of use in the Geotech forums.

chinese tester does the L-measurement the best.

https://www.aliexpress.com/item/32812240696.html?spm=a2g0o.detail.1000060.1.61f82881B5eqCZ&gps-id=pcDetailBottomMoreThisSeller&scm=1007.13339.99734.0&scm_id=1007.13339.99734.0&scm-url=1007.13339.99734.0&pvid=bf4246a1-f70a-4e20-9d12-917d41db866b

1486 orders

https://www.aliexpress.com/item/32812240696.html?spm=a2g0o.productlist.0.0.61193866K0IsRU&algo_pvid=b88f03bf-5b43-4331-94d7-5c61e6da7c84&algo_expid=b88f03bf-5b43-4331-94d7-5c61e6da7c84-5&btsid=836b90d6-ddf6-4180-9876-08802aa914e7&ws_ab_test=searchweb0_0,searchweb201602_4,searchweb201603_55

or take a data from a table.
BTW i have huge diggest of working soft of L measurement and every was checked by me.

[kt315]

put that here

http://depositfiles.com/files/l8jis38z0

[Nandor]

Or simply use the Coil Calculator
which is now celebrating 10 years of use in the Geotech forums.

I use it, it's bookmarked. Thank you for your work George!

[barwildi]

Look at this video:

https://www.youtube.com/watch?v=Ff5xOENID7w

Then go here:
https://www.robkalmeijer.nl/techniek...e48/index.html

This circuit was posted awhile back in the Tools section by Teleno. Thread titled: "Measuring coil inductance and parasitic capacitance." I posted a spreadsheet in there which will make all of the calculations for you.

I have built and used this circuit myself and it works great, especially for comparing coils. It provides 3 good bits of coil info: inductance, parasitic capacitance, and SRF from only two frequency measurements (cap in-circuit and out of circuit). What's really unique about it is the fact that it does not require a scope, signal generator, nor anything expensive - only a cheap frequency counter (Ebay, Ali, etc.) and the circuit itself.

For a large percent of hobbyists on a budget, this is a great little 3-in-1 tool and highly recommended in my book!

b

[dbanner]

This circuit was posted awhile back in the Tools section by Teleno. Thread titled: "Measuring coil inductance and parasitic capacitance." I posted a spreadsheet in there which will make all of the calculations for you.

I have built and used this circuit myself and it works great, especially for comparing coils. It provides 3 good bits of coil info: inductance, parasitic capacitance, and SRF from only two frequency measurements (cap in-circuit and out of circuit). What's really unique about it is the fact that it does not require a scope, signal generator, nor anything expensive - only a cheap frequency counter (Ebay, Ali, etc.) and the circuit itself.

For a large percent of hobbyists on a budget, this is a great little 3-in-1 tool and highly recommended in my book!

b

Yes, I remember the thread, that's why I was able to recognise what the guy in the video was up to, since I had been familiar with this circuit from before.
The spreadsheet you posted was very helpful, as it did make all the calculations.
Modern LCR meters are very affordable, and quite good, but I still love the old vintage stuff and the old measuring techniques.

[godigit1]

Another one of his vids.

https://www.youtube.com/watch?v=RhS8m38ef0Y

Set up for using a o scope to measure inductance.

[chuubaba]

Experts/ Members Which Chinese toy toy can serve as a function generator for making M.D coils? Or at least Pi coils for D.P?

[homefire]

I have one of these that does some Limited Function Generation stuff. You can not measure while it's outputting a signal. https://www.banggood.com/GM328A-LCD-...r_warehouse=CN