Calculus disintegrating apparatus

A calculus disintegrating apparatus, which comprises:

• first and second electrodes provided separately from each other;
• discharge energy source means including a D.C. power source and a capacitor arranged to be charged by the D.C. power source, wherein said discharge energy source means is connected to said first and second electrodes to apply a D.C. impulse voltage across said first and second electrodes when the capacitor is discharged;
• polarity changing means which is connected to said capacitor, and arranged to change the polarity of D.C. impulse voltage applied across said first and second electrodes in response to each discharge of said capatitor;
• wherein said polarity changing means comprises a switching circuit connected between said capacitor and said D.C. power source for selectively defining the direction in which charge current flows from said D.C. power source to said capacitor;
• and
• said switching circuit comprises a first switch connected between one end of said capacitor and the positive terminal of said D.C. power source, a second switch connected between said one end of said capacitor and the negative terminal of said D.C. power source, a third switch connected between the other end of said capacitor and the positive terminal of said D.C. power source, a fourth switch connected between the other end of said capacitor and the negative terminal of said D.C. power source, a first actuator for closing said first and said fourth switches, a second actuator for closing said second and said third switches, and a flip-flop circuit having a trigger input connected to receive switch signals for alternately operating said first and said second actuators in response to each succeeding switch signal applied to said trigger input.