LED Flashlights aka LED Torches - Those that run on either one or two batteries contain a boost converter circuit to step up the voltage for the LED. Those that run on 3 or more batteries contain either a resistor or a current source or a buck converter circuit, in order to limit the current to the LED. HOME
Reverse engineered schematic diagram of an inexpensive LED flashlight which runs on a single AA cell and has a cluster of 5 LED's:
This reverse engineered LED Torch circuit is like the above except that it drives 8 LED's instead of 5:
I do not gaurantee the accuracy or safety of any information herein.
Do not experiment with or build any of the above circuits.