A multiplier is just a way of stepping up alternating current using capacitors and diodes to make a higher voltage than that of the input voltage. Cascade multipliers are usually found in TV's and are use to accelerate the voltage for the cathode-ray tube (C.R.T.). Television multipliers usually only consist of three stages of multiplication (this is known as a voltage tripler), the one that I have built is a five stage cascade multiplier. To the right is a picture of my cascade multiplier. It is a five stage multiplier consisting of 10 rectifiers and 10 capacitors. All components are rated at 1000 volts input. I have not yet rated the output. The length of spark is about 1cm with a power input of 330 volts from a camera flash.
Pictured below is a schematic of a 4 stage cascade voltage multiplier. The schematic should help you understand how a cascade works.
Linked are two pictures of a television multiplier. Image 01 and 02. It is currently blown due to an attempted input close the the multiplier's voltage output!