Flyback Transformer Based high voltage generators

Uses a 555 timer IC to generate a 720Hz triangle waveform (at pin 2 of the IC). This waveform is of about 50% duty cycle. This triangle waveform is compared to a fixed voltage with a comparator, IC2. The fixed voltage can be varied by potentiometer VR1. The output of the comparator is a 720Hz square wave of variable duty cycle. The potentiometer must be adjusted so that Q2 is near to 0% duty cycle (ie it spends the majority of the time off)