Working of Cockroft Walten Generation for High Voltage Generation of Direct Current.

1. By : Mayursinh
Rathod

2. Introduction
• Cockcroft-Walton (CW) Generator is used for generation of
high DC voltage from low AC or pulsing DC voltage.
• It is invented by British and Irish physicists John Cockcroft
and Thomas Walton in 1932.
• But circuit is discovered much earlier in 1919 by Swiss
physicist Heinrich Greinacher.
• For this reason its sometimes also referred as Greinacher
multiplier.

3. Design
• It is made up of voltage multiplier ladder network of
capacitors and diodes.
• It connect as shown in following figure. it is three stage
multiplier.
AC
input

4. Working
• To understand working we take single stage multiplier.
• Rearrange the figure.
• Assume capacitor is
charged with 1V.
• Red plate = +ve
• Yellow plate = -ve
AC
input
AC
input

5. Working
• Assume, we give 1V AC in input.
• First half at blue node we get 2V.
• Second half we get 0V.
• And cycle repeats.
• But due to this we get pulsing DC voltage. so we add
another diode and capacitor.
• Where Red node is Ground/reference and output is taken at
white node.
AC
input

6. Working
• Now we get constant 2V
DC at white node.
• Connect both Red nodes.
• To improve voltage level
connect another stage.
• Now we get 4V at yellow
node.
• If we increase stages we
get more voltage.
AC
input
AC
input

7. Advantages
• Low maintenance.
• Simple circuit.
• No core loss.
• No copper loss.
• Low cost compare to x’mer.
• Low space require compare to big x’mer.
• Low weight.

8. Disadvantages
• As no. of stages increase, due to capacitor
impedance loss is increase.
• When supplying output current, voltage ripple
rapidly increases as no. of stages is increase.
• So it is only use where low current is required.

9. Uses
• For lightning safety testing.
• X-ray system.
• LCD backlighting.
• Traveling-wave tube amplifier.
• Electroshock weapons.
• Cathode ray tubes.
• And many more…