Joule Thief: JTBasic Testbed Running on 3 Farad Cap, 39 LEDs
NOTE: at the end of the video I say “nine times” but I should have said “Three times as much energy.” Sorry about the confusion, I’ve got volts on my brain. This is a start at setting up for an energy balance measurement run. I am only illustrating the basic features of the testbed apparatus and its performance here. Measurements and comparisons will come later when all circuit parameters are understood. It would also be very helpful if I could find a 10F, 2.7 volt ultracapacitor, too. But my local supplier doesn’t seem to carry them, so I have to work with what is on hand in the DeepBunker. I use the 3F capstack to show the voltage resulting from charging with a 1.3 V NiMH battery, then I allow the JT to run down under its 39 LED series-parallel load. The load is : JT positive output to White LED anode. White LED cathode to anode of 19 parallel green LEDs. Cathode of this string to anode of another string of 19 parallel green LEDs. Cathode of this string to JT negative output. Transistor is 2n2222, toroid is 1:1, 14 turns each, base resistor is 1K, and series CVRs are 1R in the charge circuit and 1R in the JT negative rail. NOTE: at the end of the video I say “Nine times the energy” when I should have said “three times the energy”. Sorry for the confusion … I’ve got volts on the brain. Somebody gave me a couple of boxes of those miniature toggle switches….. that’s why I’m not shy about using them. I probably have thirty or more left, and I haven’t even touched the …