Self-exciting type high voltage generating apparatus utilizing piezolectric voltage transforming elements

Claim 1

A self-exciting type high voltage generating apparatus comprising a piezoelectric voltage transforming element provided with a drive electrode and an output electrode, an oscillator having frequency determining elements establishing the oscillator frequency at a frequency corresponding to the resonant frequency of the piezoelectric element, means for coupling the output from said oscillator to said drive electrode so that said piezoelectric element produces an output voltage at its output electrode which is substantially higher than the voltage applied by said oscillator to its drive electrode, and a capacitive feedback circuit for feeding the output appearing at said output electrode back to said oscillator wheReby to lock the oscillation frequency of said oscillator to the resonance frequency of said piezoelectric voltage transforming element, said feedback circuit comprising a capacitor of small capacitance and high impedance relative to the input impedance of the point to which the feedback voltage is applied to avoid damaging said point and minimize loading of said element.