I do not know how exact this coil measurement must be.
Unless you need it amazingly accurate, you can measure a coil yourself using a simple multimeter, analog or digital. Such multimeters are available quite cheaply, going as far down as $10 here-probably not much more there.
You would need the use of a signal generator.
Here is an excellent online signal generator.
http://www.satsignal.net/ Audio Tools =>Sweepgen
Unless you need it amazingly accurate, you can measure a coil yourself using a simple multimeter, analog or digital. Such multimeters are available quite cheaply, going as far down as $10 here-probably not much more there.
You would need the use of a signal generator.
Here is an excellent online signal generator.
http://www.satsignal.net/ Audio Tools =>Sweepgen
you can do this with one dual-opamp:
The sound card impedance tester
The LMS test set uses a dual opamp to compare the voltage drop across an unknown impedance and an acurately known resistor. It is remarkably simple.
You can test inductors, capacitors, transformers, negative impedances, etc.
A PDF of the QEX article is available at www.arrl.org/qex/2005/Steber.pdf
the code can be downloaded at
http://www.arrl.org/files/qst-binaries/
just look about 1/3 down the page
The sound card impedance tester
The LMS test set uses a dual opamp to compare the voltage drop across an unknown impedance and an acurately known resistor. It is remarkably simple.
You can test inductors, capacitors, transformers, negative impedances, etc.
A PDF of the QEX article is available at www.arrl.org/qex/2005/Steber.pdf
the code can be downloaded at
http://www.arrl.org/files/qst-binaries/
just look about 1/3 down the page
Al, I get down that way about once a fortnight. If I don't get any joy in the next 2 weeks I'll deffinatly take up your offer. The gig I was going to was cancelled because the guitarist broke his arm. There will be others sometime though.
Thanks to the other guys. I don't really want to get into special projects for this. I'd probably need to borrow a meter to varify the calibration anyway!
One of my suppliers has a huge flying probe PCB test machine. I might call in that favour.
Thanks to the other guys. I don't really want to get into special projects for this. I'd probably need to borrow a meter to varify the calibration anyway!
One of my suppliers has a huge flying probe PCB test machine. I might call in that favour.
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