Voltage multipliers can be used to generate bias voltages of a few volts or tens of volts or millions of volts for purposes such as high-energy physics experiments and lightning safety testing.
The most common type of voltage multiplier is the half-wave series multiplier, also called the Villard cascade. Such a circuit is shown opposite.
Assuming that the peak voltage of the AC source is +Us we can describe the (simplified) working of the cascade as follows:
In reality more cycles are required for C4 to reach the full voltage. Adding more segments analogous to C1-D1-D2-C2, we can increase output voltage by 2Us.
While the multiplier can be used to produce thousands of volts of output, the individual components do not need to be rated to withstand the entire voltage range. Each component only needs to be concerned with the relative voltage differences directly across its own terminals and of the components immediately adjacent to it.
Typically a voltage multiplier will be physically arranged like a ladder, so that the progressively increasing voltage potential is not given the opportunity to arc across to the much lower potential sections of the circuit.
Note that some safety margin is needed across the relative range of voltage differences in the multiplier, so that the ladder can survive the shorted failure of at least one diode or capacitor component. Otherwise a single-point shorting failure could successively over-voltage and destroy each next component in the multiplier, potentially destroying the entire multiplier chain.
A single secondary winding of a transformer can drive two cascades of different polarity at the same time. Two of these can in turn be stacked. The goal is to reduce the ripple and the capacity at the same time. To further reduce ripple, an even number of stages is used and the connecting column gets bigger capacitors.
A common type of voltage multiplier used in high-energy physics is the Cockcroft-Walton generator (which was designed by John Douglas Cockcroft and Ernest Thomas Sinton Walton for a particle accelerator, for use in research that won them the Nobel Prize in Physics in 1951).