Ok. Now there's Another issue. Switch 1 Melted. As in Really melted to the heatsink. Maybe it's because the transistor has already been used before, but anyhow, I am gonna change it.

 

i made a quick NON "WYSIWYG" illustrative , simplified , functionally incomplete -- 1W output design
to show why making a regulated swiched supply from components is all hell
or does not pay off against off the shelf controllers (which have loads of circuits buried inside 'em)
. . . it's about implementing the BV output function takes at least two op amps + I/O protection takes even more components . . .
+ the circuit had not reliable start = an aditional startup circuit is required + a soft-start circuit for input voltages greater than 4.1V

________
however , your Joule-Thief Flashlight likely does'not take more than a right base resistor + finding optimum TF coils ratio and impedances for 3 to 3.7V input
. . . and (possibly -- an output overcurrent alert led so you can adjust it manually as the battery discharges and reduces it's terminal voltage)
related circuits : by Google in pictures
https://epackrat.wordpress.com/2009/12/14/ferrite-core-joule-thief/
http://electronics-diy.com/transformerless-joule-thief.php
. . .
PS! the most efficient is the JT in posts #5 & #17 -- but that is -- up to some 20mA (form single 1.5V AA AAA) . . . and they may spike large over-currents to LED-s making them age quicker than normal

 

This is somehow out of context but has to be asked. When making. A JT, you are to wrap 7-10 turns of insulated wire. And the circuit works. Then, most people say wind the primary turns first and then the secondary turns comes after. Among these, Which is correct? I am confused..

 

When I made a Joule Thief, I bent a single piece of wire into a pair then wound both at the same time.

The looped end the makes the connection that is common in the primary and secondary.

Bob

 

E.g the one here (https://upload.wikimedia.org/wikipe...0px-Conventional_Joule_Thief_with_red_LED.jpg and here. https://mad-science.wonderhowto.com...batteries-for-more-power-after-death-0134326/) is different from the one here(https://www.evilmadscientist.com/2007/weekend-projects-with-bre-pettis-make-a-joule-thief/).

 

@Miracletech what are you trying to achieve? This can become very complicated but if your goals are simple, it won't take long to find a solution.

 

Little Kids Flashlight.