Winding your own tiny inductors

[punchpeanut]

I would like to wind my own little inductors for a project I am working on. They only need to be 3uH and I seem to be having trouble finding that size.

Does anyone know of an equation for the number of turns to make one with various size wires? I found an app online, but it was a in java for loudspeaker inductors. Way too big for my project and it didn't display how the calculations were done. I would most likely just wind them around a wooden dowl.

Thanks.

 

[stappvargen]

Hi punchpeanut,

Hopefully the following thread will be of some help:

Link

/Niclas

 

[Sch3mat1c]

Just a few turns I think.

Program I like to use for air-core is coil.exe... um I'll attach a .ZIP for 'ya.

The basic approximation that we're all familiar with only applies to certain conditions; this program apparently is very accurate. It even accounts for the form capacitance!

Tim


MODERATOR NOTE: File removed at request of owner due to copyright issues.

 

[punchpeanut]

Thanks so much. I figured it would only be a few turns, but didn't want to waste time, effort, and materials to do a trial and error experiment.

 

[darkmoebius]

I know this thread is dead, but....

I contacted the author of the program coil.exe and he said it will only work for single-layer inductors and was intended for designing radio frequency inductors.

My own quick experimentation seems to confirm this. I entered all the physical values for a 0.65mH inductor(16 AWG, 1" dia., 1" length, 140 turns, 0l01 MHz) I have sitting on my desk and the software returned 270 mH for the inductance.

So, I don't think this is much use for audio since all our inductors are likely to be multi-layer.

 

[Jay]

I am skeptical of this because any program will report on what it is sent after the signal has passed through the DSP for error correction. Not unless the software in question has access to the C1, C2 error flags (and from there can generate the Ex codes you were talking about earlier). You need to have access to the raw serial data stream right after the EFM signal is demodulated. The only way I can assess errors in home CD players is to have access to those two Cs level flags in hardware. I'm not saying this can't be done, I just don't know and have learned to be very careful of where the signals come from in order to assess how valid the numbers would be.

CDROMs use protocols used by computers so it is a lot easier to write program that read whatever in the memory, without hardware change. With regular CDP which also run at 1x ('real time') this is not so.

C1/C2 is a standard (but who is enforcing?) for firmware and optical drives but how it is implemented could be different.

C1/C2 is "flagged" in DSP level to be used with CIRC and interpolation circuitry. Software should be written to red those "flags". Inaccuracy can happen, depends on the program and how the DSP/chip "reports" those C1/C2.

The result of this typical software has been shown by Mark when he showed the report for the 50 TDK discs before. Skeptical? I think, may be we are barking on the wrong tree...

For us, me especially, there are main objectives to be addressed:

(1) How things will affect sound (audible effect)
(2) Durability of the transport
(3) Convenience of the transport operation

Those objectives, when analysed critically, even lead me to believe that CD is not the way to go.

 

[DF96]

Posted in wrong thread??

 

[Jay]

Posted in wrong thread??

Yeah, don't ask me... ) I have never been on this thread before (it was not on my subscription page).

I opened my subscription page, right clicked on the "Quality CD-Mechanisms are long gone - let us build one ourselves!" thread and opened in a new tab. Replied one post and submitted (post#493), then replied another post and submitted but strangely the site said that I couldn't post in a few minutes after my last post (which I thought had been long minutes ago). So I had to repost and it went to the correct thread (post#494). Somehow, the previous submission (that I didn't think I have pressed the submit button) posted on this thread. That's Quantum Mechanics

 

[AndrewT]

I am occassionaly see a warning telling me to wait for 60seconds before posting.

The system thinks I have posted the same reply twice and rejects the second post as too quick.

I can't tell if this is a faulty keyboard that is sending two requests due to contacts bounce or it is DIYaudio that interprets the posts as having been sent twice.

I also get pages not linking after clicking on an icon. Some helpful Members tell me to clear a cache, but that never seems to solve it. Even shut down and restart does not solve that. Pages just won't link, until the next day.

I wish I undersood computers, they are as difficult to fathom as women.

 

[Jay]

I can't tell if this is a faulty keyboard that is sending two requests due to contacts bounce or it is DIYaudio that interprets the posts as having been sent twice.

In my case, the question is why it went to a thread, a dead one, that I don't know nothing about First time BTW.

I wish I undersood computers,

When I taught programming to beginners, I noticed that they didn't realize that for programmers, problems are expected and even welcome. They tried to avoid errors as if it is possible. Very different state of mind that affect the speed or how they write their code.

 

[DF96]

I think the warning about double posting happens when a post goes through but the acknowledgement gets lost, so the local code repeats the request. There is a UK wireless website which uses the same forum software which until recently did not use the double-posting check so there people could do double posts.