Late night thoughts
I'm done playing with my little circuit for the night, so before I go to bed, a few thoughts.
Yes, it does work, despite not being supposed to, at least according to a simulation. Not bad, either. This power supply fascinated me with the possibility of running low-powered 5-volt circuits from just a single, cheap AA cell, rather than the more expensive 9-volt battery and 5-volt regulator.
It's an odd circuit. One odd thing I noticed: I took Eric's advice and changed the base resistor. But no matter what value resistor I used, I got the same results, more or less. ?!?!?
Another strange thing: I was actually using a regular silicon diode (1N4007) instead of a Schottky as per the circuit diagram. But when I tried a Schottky, the output actually went down! Same with a 1N4148. It only seems to like the 4007 for some reason.
It turns out to be a not-very-efficient boost converter. According to my measurements, I'm getting somewhere in the 25-30% range. Even my little 3V--> 9V power multivibrator is better than that.
But then, the original design really didn't need to be all that efficient. It was for a one-use camera with a flash, and as long as it could fire off a full roll of film's worth of flash exposures without failing, perhaps after sitting on the shelf a year or so, it was fine.
It's intriguing to try to take a circuit like this, made for a very specific purpose, and try to hack it for another, similar but different purpose.
If anyone has any suggestions, you know where to leave them. I'll be reading.