Re: Zapper : scientific base, safety, FDA and so on...

>- It is normal to be 5-6V.

Actually not. Two points to present.

First, Using a standard DVM will only give about half of the actual voltage in a standard zapper as the duty cycle is 50 percent. Because a DVM will usually integrate the voltage, it only reads about half of real. There is also a dependency on duty cycle which is where the UZ looks like it is outputting more voltage. It has a duty cycle of over 95 percent. Not a true square wave.

The other is that there is a dependency on what chip you use. A standard 555 will only output about 8.5 volts on a 9 volt battery whereas a good chip like the TLC555IP will output 9.6 volts on the same battery. All readings mentioned above are "No Load Readings"

You will find that when the zapper is attached to a load (the body for instance), the voltage at the output will decrease inversely according to the resistance. The current limiting resistor "absorbs" more voltage as the body resistance decreases and current increases.

Ideally, the signal should always be checked with an oscilloscope as the squareness of the waveform is more important than the voltage and the sharpness of the leading edge is probably the most important factor to consider and this can only be seen with an oscilloscope.
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