I had hundreds of pictures in my old watsonseblog blog, which went away when the blog was removed. I’ve probably got the pics somewhere in the thousands of digital pictures that I’ve taken, but I haven’t got the time or inclination to go back through all of the pics to find them. So I just pull out one of those old circuits and take another pic of it – it only takes a few minutes.
This one was probably before 2011, maybe 2010, when I found some of those tiny toroids at surplussales.com (it’s the T231212T). The core is less than 1/4 inch or 6 mm O.D. They have a high permeability and work well for making a really small JT. And they’re inexpensive, about a quarter apiece. I wound this one trifilar, with three strands of 30 AWG (.25mm) enameled, and put two of the windings in parallel for the primary winding. I think the wire length was about 7 inches or so.
The perforated circuit board is 1 inch (25mm) long by 7/16 inch (11mm) wide. This one is quite a contrast to the big monster toroids I blogged recently.
Back to experimenting…