I thought it was AC and the diode does not make it all positive DC. I think the Beck zapper partly works due to the frequency itself. It's not bad, but it not anywhere what Beck said it would do. The Schumann Earth frequency in itself, can perform almost miracles sometimes. John Crane said 3.915 hertz and 4 hertz were good for "healing and regeneration". But for a viral issue you'd probably want 2489 hertz as a good all around frequency.