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So... in keeping with my insufferable miserly behavior, I have decided that the prices being asked for coils is becoming offensive to me. My wife says I am a petty ba****d, but to each their own...
I understand I need magnet wire - are their more and less desirable coatings?
Bobbins - sources?
How many feet of wire is there in, say, a typical 18awg, 0.20 mH air core coil? According the charts I found here, 18awg copper has about .00751 ohms/foot. If I look at this inductor, it has a DCR of 0.20 ohms which implies >25 feet of wire in a coil. Am I thinking correctly?
Doing some preliminary shopping for magnet wire turns up prices ranging upwards from $10-20/pound. So it looks like I can save a little money given one source I found is offering 100 ft of 18awg magnet wire (1/2 pound) for ~12 dollars. This would appear to be enough wire to wind four 0.20 mH inductors, which would cost me ~15 or so.
Personally, saving three dollars makes me happy - until I think of the time involved in counting hundreds of turns of wire around a little plastic bobbin.
Which brings me to my next question. Erse and Jantzen and them must bathe their air cores in something - what might it be? We have some UV activated conformal coating at work, is it something like that? We use it because it has an extremely high dielectric strength... Is that one of the reasons (other than to hold it all together) that the big boys give their coils a bath?
I guess what I am wondering is, if a guy can spend dozens of hours in the garage building speakers or a guy can spend all winter tying flies to go fishing, is the time spent winding worth the few bucks I save?
I understand I need magnet wire - are their more and less desirable coatings?
Bobbins - sources?
How many feet of wire is there in, say, a typical 18awg, 0.20 mH air core coil? According the charts I found here, 18awg copper has about .00751 ohms/foot. If I look at this inductor, it has a DCR of 0.20 ohms which implies >25 feet of wire in a coil. Am I thinking correctly?
Doing some preliminary shopping for magnet wire turns up prices ranging upwards from $10-20/pound. So it looks like I can save a little money given one source I found is offering 100 ft of 18awg magnet wire (1/2 pound) for ~12 dollars. This would appear to be enough wire to wind four 0.20 mH inductors, which would cost me ~15 or so.
Personally, saving three dollars makes me happy - until I think of the time involved in counting hundreds of turns of wire around a little plastic bobbin.
Which brings me to my next question. Erse and Jantzen and them must bathe their air cores in something - what might it be? We have some UV activated conformal coating at work, is it something like that? We use it because it has an extremely high dielectric strength... Is that one of the reasons (other than to hold it all together) that the big boys give their coils a bath?
I guess what I am wondering is, if a guy can spend dozens of hours in the garage building speakers or a guy can spend all winter tying flies to go fishing, is the time spent winding worth the few bucks I save?
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