Without seeming to support the pseudo-science inherent in the concept <g> the point of the 'zapper' seems to be to generate a 'frequency' or pulsed voltage, which, in the case of 'tapping' is just the most primiitve method.
Since we're just talking 9 volts, all you need to make a better one yourself is a variable resistor, a capacitor and some wire.
Here's an example:
http://hyperphysics.phy-astr.gsu.edu/hbase/Electronic/relaxo.html#c2
Go to the library and look for any circuit diagram for a 'blinker' circuit. You should be able to vary the frequency with the variable resistor. Naturally, if you want some *specific* frequency, things get more complicated
Zinj
Since we're just talking 9 volts, all you need to make a better one yourself is a variable resistor, a capacitor and some wire.
Here's an example:
http://hyperphysics.phy-astr.gsu.edu/hbase/Electronic/relaxo.html#c2
Go to the library and look for any circuit diagram for a 'blinker' circuit. You should be able to vary the frequency with the variable resistor. Naturally, if you want some *specific* frequency, things get more complicated
Zinj