Home made inductors

[jimangus]

Hello everyone,

was sitting hear listening to my prenounced midband DIY loudspeakers and suddenly thought. Is it possible to make my own inductors.

I did a little web search and came up with this

http://www.arrl.org/tis/info/pdf/9708033.pdf

According to this it is quite easy. After a bit of messing about using old cable bobbins and counting up the windings measuring the diameter and length etc i think i have made a 2uH inductor (or there abouts).

Does this page tell the whole truth? Does the calculations seem correct ?

Regards

Jim

[Andrew]

Hi Jim,

Well no reason why it won't work.

Have you checked the inductance is reasonably flat with signal level? I expect that's the rub....

cheers,

-- Andrew

[Paul Barker]

you would need to build up more than one layer for 2microH, you get more inductance per turn for turns which go outward in diamater than you do for turns which are side by side.

For your woofer you want to use as thick a wire as you can obtain. I had some 2.5mm diameter, but it's now all gone the bobin cost me £50 or thereabouts. it made a 3kva 3 phase voltage converter (autoformer), the Ariel crossover inductors and now some 4.2 mH inductors for the OB's.

I don't have a tape handy but fortThe 4.2 mH I used large transformer bobbins I think they are EI240, there are about 8 layers. I didn't count the turns, ofr such projects I just build up the layers and then measure the inductance when it's nearly full, adjust extra turns required, measure again, adjust, until desired inductance obtained.

For the Ariels I did a calculation as my inductance meter was broken at that time, when we got them to Mark Jeff's where he had an inductance meter they were cock on. I'll see if I can find the calculator for you and post the link.

[NickG]

If you don't have a inductance meter, something like this is nice to have on the shelf

http://cgi.ebay.co.uk/Marconi-LCR-un...QQcmdZViewItem

[jimangus]

How much`is an inductance meter ? I have no idea just a question. Also where would i get one from ?

Cheers guys


i am actually at this moment alittle squiffy. HIC !!!

Jim

[jimangus]

Hi guys, after having a scan about the measuring of inductors could be done from a home made rig a battery and simple multimeter. Or i could buy one of these for £29 from farnell.

http://www.farnell.com/datasheets/65870.pdf


Just a thought could i wind inductors from silver wire ? Wil it still work ? Will the sound improve ?

Jim

[petercom]

It will work, it will be expensive, the sound will improve only if you think silver sounds better than high purity copper. Bear in mind that silver is softer than copper so is more likely to stretch when you wind it and, whereas copper can be obtained with an insulating lacquer skin, silver will have to be insulated with a thin, insulating sleeve.

[NickG]

That link I posted will allow you to measure inductance up to 100H and caps up to 100u, also measure Q and d, which the multimeter will not let you do.

[jimangus]

Originally Posted by petercom

It will work, it will be expensive, the sound will improve only if you think silver sounds better than high purity copper. Bear in mind that silver is softer than copper so is more likely to stretch when you wind it and, whereas copper can be obtained with an insulating lacquer skin, silver will have to be insulated with a thin, insulating sleeve.

http://www.wires.co.uk/acatalog/SILVER_ENAMELLED.html


WWhat about this then buddy. perfect for winding inductors. I think ? Waddaya reckon ?

Jim

[jimangus]

Originally Posted by NickG

That link I posted will allow you to measure inductance up to 100H and caps up to 100u, also measure Q and d, which the multimeter will not let you do.

it iwould be good but it may be a bit out of my price range. We will have to see. What are Q and d ?

regards
jim