| 摘要 |
A method for determining the voltage current phase relationship of a piezoelectric phacoemulsification handpiece includes the steps of obtaining an AC voltage signal corresponding to the operating AC voltage of a piezoelectric handpiece and obtaining an AC current signal corresponding to the operating AC current of the piezoelectric handpiece. From said AC current signal, onset of a current cycle is determined and after onset of the current cycle, a voltage (VI) corresponding to a time necessary for the AC current signal to reach a maximum value is produced. Also, after onset of the current cycles, a voltage (Vv) corresponding to a time necessary for the AC voltage signal to reach a maximum value is produced. Using an A/D converter, a digital output (Dv) corresponding to (Vv) is produced and a digital output (DI) corresponding to (VI) is produced. Comparing (Dv) and (DI) determines the phase relationship between the voltage and current of the piezoelectric phacoemulsification handpiece.
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