Joule Thief very very low input 0136 volt
This Joule Thief work at a very very low input voltage from 0.125 to 0.35 volts and the output voltage is 2.7 volts, to the LED. An ordinary Joule Thief work down to 0.6 to 0.8 volts, because of losses in the transsistor. Voltage ratio is 1 to 21. So if the LED need 5 mAmps, the battery must give over 100 mAmps.