I am trying to implement a very simple solar charged night garden light. Schematics is here:Basically a solar panel charges a battery. When the solar panel output is low (at night), a joule thief circuit lights a led.
The joule thief part works just fine, the problem is that the dark detector (2n3906 + 4.7K resistor) never triggers the joule thief and I cannot understand why.
Here are the pictures of the breadboard:
If I bypass the dark detector connecting the positive wire from the battery to the center of the transformer (moving the yellow wire from row 16 to raw 14) the led lights up.
Thanks a lot for your time.