Hi Al, The rectifier is required so that the PWD can compare the DC levels at Vd1 and Vd2. L1 & L2 form a step up transformer of approx 1:22 , so 12V swing on L1 , gives a 22*12V on L2. The Neon requires about 170V to 'strike' [ flash] E Could it alsmost be described as a comparator and pulse width pass filter?
