Thundervolt zappers have 4 frequencies because humans have 4 extremities, i.e., ideally, one frequency into each arm and leg for max body penetration. A Thundervolt senses the internal electrical condition of the user, and adjusts the 4th frequency to match, using dual opposing waveforms and .45 volt positive offset. The two zinc handholds and two footpads plug into the 4 output terminals and all 4 are used together. Four color-coded LED's confirm the outputs work. The internal condition of the user is a measure of vitality and can be easily tested, monitored, and documented.
After one zap, the male plug-ins are alternated, and switched again for the third zap. Parasites, molds, toxins, bacteria, viruses, fungi and worms cannot stand this mixed assault. The frequency tolerance is 5% because this increase the stress on pathogens. The output voltage 10 volts; the current is a few milliamps. This is explained in the Theory and History links of the webpage.
Thundervolts require over 10 volts to operate. Nine volt batteries are not sufficient because of waveform deterioration, weak supply voltage and repeated costs of batteries by users. Once Dr. Clark solved the positive offset problem, her utility-powered commercial signal generator was just as effective as her son's battery unit. She states this on page 15 in her book. Therefore, Thundervolts are powered by UL-listed isolation DC wall transformers, fuses and selective circuitry. The electric shaver industry also uses wall transformers, as do millions of handheld devices. None of these would be allowed if there was any danger to the consumer. I hope this answers your questions. Sincerely yours, Steve Coffman