This is just an alternative PWM for hydroxy generator . It is made from relay, capasitor and tripot variable resistor. The drawback is it can only reduce current to up to 40%, depend on relay build. Inspired by Imhotep Radiant Oscillator.
Should be more heat resistant the the solid state version.
Video:
http://www.youtube.com/watch?v=grs4HGr_pag