A fluid treatment device comprising: a pulse generator having a first terminal and a second terminal to connect to a source of electrical voltage providing a pulsed voltage wave signal between a third terminal a fourth terminal, and a first circuit having at least a first coil and a second coil, each positioned adjacent to a fluid conduit such that they generate opposing fields and electrically connected to said third and fourth terminals (34, 35) and at least one capacitor also electrically connected to said third and fourth terminals (34, 35), said first circuit having a total inductance L, a total capacitance C, and a resonant frequency, wherein said total inductance and said total capacitance of said first circuit are adjusted such said resonant frequency is in the range of approximately 10,000 Hz and 100,000 Hz, said pulse generator arranged to generate a pulsed voltage wave with a frequency approximately equal to said resonant frequency of said first circuit, said fluid treatment device further including a second circuit arranged to be connected to an AC power supply (56, 114) which may be the same or different from the source of electrical voltage for said pulse generator, said second circuit also having third and fourth coils (110, 112), each of said third and fourth coils (110, 112) having first and second parts (110a, 112a, 110b, 112b), wherein the first and second parts of said third coil are positioned adjacent to said fluid conduit and spaced apart from one-another, wherein the first and second parts of said fourth coil are positioned adjacent to said fluid conduit interposed between said first and second parts of said third coil, said first and second parts of said coils configured such that the first part of each coil generates a field in a direction opposite to a field direction generated in the second part of each coil, said second circuit further comprising a pair of oppositely arranged diodes (180, 182) to power said third coil during one half of an AC cycle and to power said fourth coil during a second half of said AC cycle. a pulse generator having a first terminal and a second terminal to connect to a source of electrical voltage providing a pulsed voltage wave signal between a third terminal a fourth terminal, and a first circuit having at least a first coil and a second coil, each positioned adjacent to a fluid conduit such that they generate opposing fields and electrically connected to said third and fourth terminals (34, 35) and at least one capacitor also electrically connected to said third and fourth terminals (34, 35), said first circuit having a total inductance L, a total capacitance C, and a resonant frequency, wherein said total inductance and said total capacitance of said first circuit are adjusted such said resonant frequency is in the range of approximately 10,000 Hz and 100,000 Hz, said pulse generator arranged to generate a pulsed voltage wave with a frequency approximately equal to said resonant frequency of said first circuit, said fluid treatment device further including a second circuit arranged to be connected to an AC power supply (56, 114) which may be the same or different from the source of electrical voltage for said pulse generator, said second circuit also having third and fourth coils (110, 112), each of said third and fourth coils (110, 112) having first and second parts (110a, 112a, 110b, 112b), wherein the first and second parts of said third coil are positioned adjacent to said fluid conduit and spaced apart from one-another,