evidence: - In recent years, the so-called zappers – electric waveform generators to kill pathogens and support the body. The principle of operation and the construction of new discs is extremely difficult, it is more difficult to rationally explain their therapeutic effect. Currents of different frequencies have long been used in classical medicine, but today’s popularity of different varieties of zapper is mainly related to the content of the book "The Cure for All Diseases", written by Dr. Hulda Clark. In 1988, Mrs. Clark began experimenting with alternating waveforms, first at 1000 Hz, then at higher and higher frequencies. As she writes, she stated the presence of resonance. This applied to the human body as well as parasites, bacteria, viruses, mold and even toxins. He claims that all germs and parasites had characteristic resonance frequencies. At the same time, the author decided that a very good effect can be obtained by using only one, relatively low frequency of 20 … 40 kHz, when the output waveform has a rectangular shape and contains a constant component. In his book, he proposes building a zapper – a device to destroy parasites in the body. Zapping refers to the exposure of germs to an electric current of a certain frequency, the name derived from the slang term zap – "attack, kill, destroy".