I bought some ‘high current’ chokes from Jameco, P/N 642855, which are 390 uH. They’re bigger than average, and mount axially; in other words the leads are at opposite ends of the cylindrical package. They are made by winding relatively heavy copper wire onto a ferrite bobbin. The bobbin is then covered by a piece
(Read More…)
I went on a Joule Thief building binge for a few hours last night, making up some germanium Joule Thiefs after I found a small box of old unidentified germanium transistors that I had forgotten about. I used a small piece of the “Woodsies Squares” thin birch plywood about 1/2″ by 1″ (12.5 by 25
(Read More…)
I took this picture by holding a two lens pocket magnifier in front of my point-n-shoot camera. I came out good considering that the magnifying lenses had no color correction. That’s why there’s a slight color fringe at some dark and light points. This is an old germanium transistor from the late ’50s or early
(Read More…)
I had no problems getting the 2SK170 JFETs from Futurlec. They were on tape. I don’t know what manufacturer, but they are not Toshiba. Right now, I think a lot of the major semi makers are abandoning through hole parts, and going to surface mount only. To get a through hole part, one may have
(Read More…)
I bought some Jameco inductors, among them was Jameco Part No. 371215, which was a closeout sale of $.49 each. Their picture shows it as uncovered wire, but all of the ones I got had a black heat shrink tubing around the circumference. The wire diameter was 24 mils, or about 23 AWG when the
(Read More…)
Using a resistor in series with the LED or supply The reason for using the 1 ohm current sensing resistor between the LED cathode and negative is that it has lower resistance than the meter. The meter’s internal resistance varies depending on the range setting so one can’t depend on getting consistent readings between ranges.
(Read More…)
Paul emailed and said he has built his 12th Joule Thief. Man, this guy is Helen Wheels – an even dozen in a matter of a fortnight (or week or two, I forget which). I’ve been puttering with the TE Flashers. I made most of them on small pieces of “Woodsie” wood that I got
(Read More…)
I found this LED website in Germany, I like it because it’s LEDs, LEDs, and more LEDs, and not an electronics parts distributor. The LEDs are broken down into various types, standard, high power, etc., etc., etc. I’m looking for a similar website of a store in the U.S. I figure it would be best
(Read More…)
Quantsuff sent me a link to a short video of a toroid being wound using the cheating method. The toroid is broken in half, the turns are wound on and the two halves glued back together. Quite some time ago I participated in a discussion about doing this or a similar method and I’m not
(Read More…)
I have built several of the “Single Cell Flasher With Two Year Battery Life” flashers found at Pigeonsnest.co.uk and they flash for what seems like eternity – they’re real misers when it comes to battery current. But the flash is somewhat anemic and I had never tried this type flasher with any color LED other
(Read More…)
