It’s summertime in Southern California, which means a surge of mosquito trying to harvest human blood. I do not appreciate being an excellent source of protein, and the weapon I find most satisfying for fighting back are electronic mosquito zapping paddles. Some call them electronic flyswatters but I think that’s a misnomer. At least around here, where our usual species of flies grow far too big to be caught in the mesh.
This one says “Electronic Mosquito Trap” right on the handle. There is an activity light visible through a clear plastic window, and barely readable on that clear plastic is “Little Angel”, possibly a brand. Powered by a pair of AA batteries, the voltage is drastically increased to build up a high potential difference between layers of metal meshes. When a mosquito tries to fly through those layers, they short the circuit ending their bloodsucking quest.
A household commodity made at great volume for low cost, they are practically disposable. This particular zapper was damaged when one of my vigorous swings crashed into the wall. The shattered rim of brittle plastic is cosmetic, but the mesh has also been bent so that the layers touch. It is no longer possible to build a high voltage potential between mesh layers, so it is time for a teardown before disposal.
I expected a voltage boost converter circuit within, implemented in the simplest and lowest cost method possible. I only recently learned to recognize a boost converter when I see one, and this guy certainly qualifies. Implemented with large through-hole components, it looks we have the basics of: a transistor, a coil, a capacitor, and a diode.
Boosted voltage are sent to metal layers via these wires, whose insulation was damaged during assembly at the factory. At least the plastic is still an insulator.
Indicator light wires were also damaged in assembly.
The yellow output wire was connected to the center layer of the mesh sandwich, the two red output wires (both soldered to the same point on the circuit board) are connected to the top and bottom meshes.
Learning more about boost converters is on my to-do list. After I have a better idea of what’s going on, I want to look at this circuit again. Perhaps I can make my own improvements on a mosquito zapper paddle!