When I switch on a fly swatter for some time, then turn it off and touch it with a conductive material(such as a pencil), I get a momentary spark. The spark is not continuous that I get when the device is on.
Why is causing the spark? Is some charge getting stored in it?
Yes. A fly swatter often charges a capacitor to store the charge for the spark; this capacitor might only leak off slowly when the fly swatter is off. You can still discharge this capacitor yourself by inducing the spark. Then, note the capacitor does not recharge because the fly swatter is off.
