For the purpose of learning, I have tear down a small mosquito zapper racket.
I am now trying to understand how the circuit is working (which goal is to produce high voltage).
(yellow = resistor, black = transistor, red = led, gray = diode, blue = capacitor, brown = switch or wire) Battery is on the left, high voltage output on the right.
How I think it works : the transistor generate pulse (square wave?) which is fed into the transformer. The transformer multiply voltage, then voltage is rectified trough the diodes, and finally stored in the big capacitor. Can anybody confirm this ?
Also some other things are still unclear to me :
- How does the 6 pins transformer works ? I already saw 5 pin transformers (http://en.wikipedia.org/wiki/Center_tap) but never that one.
- How does the transistor generate the pulses. I have seen some led blinking circuits but they always involve a transistor and a capacitor.
- What is the purpose of the two resistors in parallel with big capacitor? (to limit voltage, for safety ?) and also why do we need the small blue one ?
I tried to reverse-engineer the circuit. Here is the result.
I'm no sure about transistor configuration (eg : if base, collector and emitter are correctly set) and same about transformer.
EDIT2 : I open racket again. I found transformer pin-out by measuring it with multimeter (as jippie suggested). I also found transistor configuration by reading number information on it and checking datasheet. It seems what Spehro Pefhany suggested was right.