Van de Graaff v Cockcroft Walton Multiplier

InventorHeinrich Greinacher but named after John Douglas Cockcroft and Ernest Thomas Sinton WaltonRobert J. Van de Graaff
Year of invention19191929
Original UseParticle acceleratorsParticle accelerators
Method of chargingGenerates a high DC voltage from a low-voltage AC or pulsing DC input by using a cascade of diodes and capacitorsUses a moving belt to accumulate electric charge on a hollow metal globe via two rollers of differing materials using the Triboelectric effect
Output VoltageRoughly Dependant on AC input voltage to the multiplier times the number stages. Each stage is 2 capacitors and 2 diodes.Dependant on the diameter of the sphere and distance from any earthed objects.
Output CurrentRoughly Dependant on the input current to the multiplier times 1/ the number of multiplying stages.Dependant on the speed of the motor and the width of the charging belt.
AdvantagesHigh reliability, no moving parts, not susceptible to dirt or moistureSimple construction, easily scalable.
DisadvantagesLarge losses when scaling up for voltage, Complex, Electronics easily damaged by electrical dischargesDirt & moisture affects operation. Unreliable without regular maintenance, Belt wears out over time.
More detailshttps://en.wikipedia.org/wiki/Cockcroft%E2%80%93Walton_generatorhttps://en.wikipedia.org/wiki/Van_de_Graaff_generator