Bad Hair Day

The __X__ generator was developed, starting in 1929, by physicist ___X___ at Princeton University. The first model was demonstrated in October 1929. The first machine used a silk ribbon bought at a five-and-dime store as the charge transport belt. In 1931 a version able to produce 1,000,000 volts was described in a patent disclosure. This version had two 60 cm diameter charge accumulation spheres mounted on borosilicate glass columns 180 cm high; the apparatus cost only $90 in 1931.

So ID X

Answer (highlight to read) : The Van De Graff Generator