A system for providing position information of a target mobile communication terminal whose position is to be found out. The actuator system is arranged such that the threshold value of the maximum permissible power in the power limiting circuit may be changed, and that this change may be performed via a key on the handset. Metadata is implicitly associated with user profiles, activity entities, expressions, or other data entities based on user behavior using metadata collector. The coupling member is configured to be decoupled from at least one of the first elongate member and the second elongate member when the medical device is in a second configuration. The driving signal includes a plurality of driving pulses, and in each recording period, at least one driving pulse includes a portion varying from a discharging level to a medium level to charge the piezoelectric element to eject a liquid droplet, and a subsequent portion varying from the medium level to a target level to re-charge the piezoelectric element to the target level.