A voltage multiplier circuit is an arrangement of capacitors and rectifier diodes that is frequently used to generate high DC voltages. This kind of circuit uses the principle of charging capacitors in parallel, from the AC input and adding the voltages across them in series to obtain DC voltages higher than the source voltage. Individual voltage multiplier circuits (frequently called stages) can be connected in series to obtain even higher output voltages.

Spellman has pioneered the use of voltage multiplier circuits at extreme voltage and power levels. Spellman's engineers have repeatedly broken limits normally associated with this type of circuit, as they continue to lead in the development of this area of high voltage technology.