Introduction: Low Power Consumption Joule Thief
This is a improved version of the "traditional" JT, the idea is to obtain a very low power consumption. I seeked a way to light a 3v LED with as low as possible battery drain.
Direct link to bigger schematic image https://www.instructables.com/file/F8QACNGGAJUTTOO/?size=ORIGINAL
Step 1: Schematic
Here is my schematic and the schematic for a standard JT.
Parts List :
Q1 - BC547C
R1 - 1k 1/4W
SW1 - Switch
C1,C2 - 10nF ceramic capacitor (marked with 103)
D1 - 1N4148
LED - any 3 volt led
a toroid ferite core and wire
see my outhe instructable for details on how to make the winding https://www.instructables.com/id/How-to-make-a-Joule-Thief/step3/Winding-the-toroid-transformer/
Step 2: Observations
#1 - the cap in paralel with the LED lowers the drain of the LED resulting in the posibility to add more leds
#2 - on same settings bettery drain :
2N3904 - 20mA
2N2222 - 41mA
BC547C - 2,6mA
BC547C saturation voltage is 0.2V
some calculations :
(1.5V x 0.0026A) / (3.2 x 0.0013A) => 93,75%
We have a be nice policy.
Please be positive and constructive.