Description:
Oct 2018
A Joule Thief circuit powers a bright white 3V LED with a single 1.5V AA battery that can go as low as 0.9V and maintain the same brightness. The electrical theory behind it is somewhat amazing and involves turning on and off the LED so rapidly that it is invisible to the naked eye.
I did a breadboard prototype before designing the printed circuit board (PCB) on a new web app called EasyEDA. I then ordered 10 pieces of the PCB from China at an astounding low cost of US$2!
Images:
lohjianhui 