Parece que a chave de fenda sonora evoluiu ao longo do tempo com uma série de novas funções. Isso só faz sentido, porque o Doutor provavelmente mexer com isso constantemente quando ele está entediado.
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The screwdriver had a multitude of settings and different versions of settings. The Tenth Doctor told Rose to use "setting 15B" to triangulate the source of the ghosts (TV: Army of Ghosts) and used 34-H to sink a ship (COMIC: Second Wave). It had a setting 85 that undid security codes to unlock doors. (TV: The Lazarus Experiment) The Ninth Doctor told Rose to use setting 2428D to re-attach barbed wire. (TV: The Doctor Dances) Sarah Jane used the Theta Omega setting to melt plastic vines. (TV: The Android Invasion)
The different versions of the Doctor's sonic screwdrivers exhibited different capabilities and uses, such as the interception of signals ranging from transmat beams to conscious thought; (TV: The End of the World) medical diagnostics and repair of organic parts; (TV: The Empty Child, The Vampires of Venice) cutting, but also re-attaching materials such as barbed wire; (TV: The Doctor Dances) operating Earth machinery such as computers and even cash machines (at regular and high eject speeds); (TV: School Reunion, The Runaway Bride) creating a spark to light a candle or Bunsen burner; (TV: The Girl in the Fireplace, Evolution of the Daleks) pushing/lifting heavy objects; (TV: The Rings of Akhaten) and, on the rare occasion, driving screws without touching them. (TV: The War Games, The Ark in Space, The Doctor's Wife)
Although it was primarily a tool, the sonic screwdriver could also be used as a defensive weapon. The Tenth Doctor put it in a sound board to destroy the Robot Santas by overloading their sensors. (TV: The Runaway Bride) The Eleventh Doctor used it to bounce sound waves off a knife held by Melody Pond, knocking it out of her hand. (TV: Let's Kill Hitler) The Sonic Screwdriver was also capable of holding off sound waves from creatures who relied on sound in order to attack such as the Vigil (TV: The Rings of Akhaten) The Doctor also used it to try and help River Song defeat a group of Silents although River teased him by saying it would be better if he used it to "build a cabinet". However the Doctor implied that although it couldn't actually hurt the Silent's it could weaken the power of their electricity, therefore allowing him to provide River with a certain degree of protection while she shot down their foes. (TV: Day of the Moon)
Although the Eighth Doctor once claimed the device could destroy a Dalek's brain if held directly against the casing when activated, (PROSE: War of the Daleks) according to the Tenth Doctor, the device could not be used to wound, maim or kill living things. (TV: Doomsday, The Doctor's Daughter) It could destroy non-living objects or mechanisms or place living creatures in circumstances where they might die, if the situation required. (TV: The End of the World, The Christmas Invasion)