Joule Thief: JTEnhanced Current Input, Voltage Output Waveforms
It doesn’t seem right to call it a basic JT since the loopstick and capacitor make so much difference. So I’m calling the cap/loopstick version “JTEnhanced”. It is the basic circuit, using the 1K base resistor and the 2n2222a metal can transistor, with the modified loopstick for the inductor and the 70 nF poly film capacitor across the base resistor. The LED bank is the (12 parallel) + (12 parallel) in series bank, modified from the straight 24 parallel unit in the original 3-dollar flashlight. Here I first confirm that the DMM current reading — really the voltage drop across the one-ohm current viewing resistor — agrees with the average current reading from an eyeball averaging of the simple, ramp-shaped input current waveform on the oscilloscope. ( I am continually amazed at how accurate these cheapo DMMs have gotten lately. I think I paid three dollars for this one, battery included.) Next I show the output voltage waveform, and demonstrate the effect of the various operation modes on the waveforms. I hope this is interesting and inspirational. I am quite surprised by the low current draw and the brightness of the LED bank. Next I plan to try running on the 3 Farad capacitor stack (the closest to ultracaps that I have in stock.)
