Electric fly swatters (aka zapper rackets) are a cheap and easy way to get a high voltage power supply for some fun experiments. I've used one for powering a Franklin's bell as well as just making sparks. They cost only around $8 or 4 euros and can be found in many stores including Walmart, Home Depot and Maplin as well as online.

Electric fly swatter/zapper racket.

Making a spark with screw driver.

Powering Franklin's bell.

The photo below shows that the round part consists of three meshes, spaced apart. The two outer meshes are electrically connected together, but there is a high voltage between the outer meshes and the middle mesh. If a fly get's in between these meshes while the electric fly swatter is turned on then it gets zapped by a spark, killing it. You can also see these three meshes in the photo further below of the fly swatter opened up.

Also below you can see measuring the high voltage between one of the outer meshes and the middle mesh using a high voltage probe and an oscilloscope. The voltage is around 1400 volts.

The three meshes.

The measuring setup.

Showing 1400 volts.

Below you can see it opened up. The circuit is a blocking oscillator circuit, also known as a joule thief circuit.

The electric fly swatter opened up.

Electric fly swatter schematic.

What an electric fly swatter can do

Here I've used this electric fly swatter to power a compact fluorescent lightbulb (CFL) with minimal modifications.

Video - Electric Fly Swatter/Zapper Racket High Voltage Power Supply

The following video shows it in action powering a Franklin's bell and making sparks. It also includes taking it apart and some discussion of the circuit explaining how it works.

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