An inhaler is disclosed with a piezoelectric transducer (5, not shown) as a vibrator for facilitating suspension of medicament particles into an inhaled gas stream. The inhaler includes a flat bottomed medicament container substantially in contact with the transducer face. An electrical circuit for driving the transducer comprises a power supply (10), a diode (15), an inductor and an electronic switch (22, 23) connected in series and the piezoelectric transducer (5) connected across the switch (22, 23). The switch opens and closes at the lowest resonance frequency of the piezoelectric transducer. A method is also disclosed in which the transducer is driven at both a primary and secondary resonant frequency in order to reduce friction between the transducer face and medicament container.
