Winding Your Own Small Coils

Depending on what you build, you may or may not run into a lot of inductors. If you need small value coils, it is easy to make good-looking coils, and [JohnAudioTech] shows you how. Of course, doing the winding itself isn't that hard, but you do need to know how to estimate the number of turns you need and how to validate the coil by measurement.

[John] uses a variety of techniques to estimate and measure his coils ranging from math to using an oscilloscope. He even uses an old-fashioned nomogram from a Radio Shack databook circa 1972.

In fact, we get the idea that [John] really misses Radio Shack. In addition to the book, we noted guest appearances from a Radio Shack calculator and a caliper. We were a bit surprised that he didn't use a Radio Shack pen as a coil form.

Traditionally, if you wanted to keep your coils from moving much, you’d paint them with "coil dope" or "Q dope" which doesn't interfere much with the coil's desirable characteristics. You can buy it, still, but it is also fairly easy to make by dissolving styrofoam packing peanuts.

If you need a variable inductor, you can make those, too. If, however, you are making a lot of inductors, consider automation.