| 摘要 |
A nebulizer (1) includes a nebulizing circuit (10), a power circuit (11), a sampling circuit (12), a filtering circuit (13) and a controlling circuit (14). The nebulizing circuit (10) includes a piezoelectric actuator (100). During operation of the piezoelectric actuator (100), the liquid is nebulized. The power circuit (11) selectively provides electric power to the nebulizing circuit (10) so as to power the nebulizing circuit (10). A harmonic signal generated by the piezoelectric actuator (100) at a working frequency is sampled by the sampling circuit (12). A specified frequency of the harmonic signal is retrieved by the filtering circuit (13). The controlling circuit (14) controls operations of the power circuit (11) and receiving the specified frequency of the harmonic signal. By comparing the specified frequency with a predetermined frequency correpsonding to the absence of teh liquid, the controlling circuit (14) judges whether the liquid is exhausted. Once the liquid is exhausted, the controlling circuit (14) controls the power circuit (11) to stop providing the electric power to the nebulizing circuit (10). |
