Why my joule thief is turning on and off the led ? (I know, that is what actually does).. but it was on for 2 days approx, and now is flashing ~30 seconds off, ~10 seconds on; first it was flashing ~30 seconds off, 20 seconds on.
This is normal for a joule thief, I've had the same experience. What happens is the battery draw is constant and drops until the dropout voltage of the diode is reached in which case the battery current drops to near zero, thing is, battery voltage will gradually refresh to some degree over time under no load until oscillation can once again occur and the LED comes back on, again until the voltage drops too low and it turns off. I had a joule thief on a single battery blinking for over a week. The blinking rate will continue to get longer and the on till will continue to get shorter until one day it simply doesn't come back on again.
Your battery voltage is dying. Replace it with a new name-brand battery.
But since you forgot to post your schematic then we are just guessing.
I know, NOOBs cannot post anything here unless they are approved "Not Spam" by a Moderator. A real nuisance.
When my solar garden lights run out of battery charge then they turn on for 1 second then turn off for 10 seconds over and over for hours. Their voltage step-up circuit is similar to a Joule Thief.
I'm new to this forvm as much to electronics... I have built my first joule thief and it kinda works: I get light only when rubbing one of the leads against the battery! If I leave the leads to the battery correctly in place I see nothing...
The schematics used is already above... Does anyone have an explanation or I might try?
Does the LED have to be white or blue? Or can it also work fine with red, yellow, etc?
Thx in advance
I solved it: I change resistor to a lower value... But why doesn't 1k work for me?
Can it have something to do with the "quality" of my coil around the toroid? The battery is fine...