Abstract: A method of processing a liquid by an alternating electromagnetic field includes: generating DC pulses by a pulse generator; and applying the DC pulses to a parallel oscillating circuit connected in parallel to the pulse generator. The parallel oscillating circuit includes an inductor connected in parallel to a capacitor. In response to the DC pulses, self-oscillations arise in the parallel oscillating circuit, the self-oscillations producing an alternating current in the inductor; and the inductor generates the alternating electromagnetic field for processing the liquid.