Title:   Cock Croft Voltage Multiplier


   Cock Croft Walton Voltage Multiplier circuit is exclusively designed for HVE Lab UET Lahore. It comprises of 30 stages of doubler circuit each having four capacitors of 450V rating, two diodes of trr=1.5nsec (very fast) and four resistors of 10Mega Ohms 1Watt to equalize the voltage across series capacitor pair. In order to provide clearance from ground, stages are aligned vertically on account of bottom up approach. As we move forward towards higher stages the values of capacitors decrease, this concept is known as grading of capacitors. The conundrum of its being very expensive high voltage DC source is solved by increasing the frequency from 50 Hz (standard) to 10,000Hz. Inverter in push pull configuration is driven by center aligned pulses generated from STM32F3 controller. Their duty cycle can be varied from a variable resistor due to ADC coding with an intentional dead band for the safety of MOSFET’s, so output current and power can be varied if required. A smart switching supply is introduced along with center tapped high frequency EE cored transformer having turns 200*200. DC chopped wave, that we got at the secondary of transformer when low DC voltage is applied on primary center tapped point, is used to drive cock croft stages instead of the conventional AC voltage. This property has increa sed its efficiency stupendously by drastically decreasing the total voltage drop and ripple in voltage. An independent highly resistive load with high power rating (4.4 Mega Ohms 1000 Watt) is made for providing a discharging path to ground. It can also be used for grounding of other high voltage devices. A potential divider is stepping down the voltage that is given to LCD for the digital display.

Advisor:  Dr. Inam Elahi Rana  

Group Members:

Name: Fariha

Name: Amna Bashir

Name: Fizza Zubair

Name: Alina Qamar