Joule Thief– with tunable coil.ASF
This is a standard Joule Thief circuit with a tunable inductor coil. The simple one transistor circuit is powered off one 1.5 volt AA battery and is driving multiple LEDs in two locations. The coil is hollow and a ferrite slug is used to adjust it’s three windings into resonance. A potentiometer at the transistor base is also used to fine tune the circuit. The 27 LEDs are on a Dr. Stiffler SEC tower and are– IN SERIES! The one LED on the board is in the standard location off the collector. All of the LEDs can be made to light at the same time.