Sonic screwdriver

The sonic screwdriver, also called a sonic probe or simply the sonic, was a highly versatile tool used by many people throughout the universe, the most prominent of them being the Doctor. They modified and ostensibly upgraded it over the years, giving it an increasing number of applications. Early versions were used mainly for the picking of locks and for projecting sound so as to, for example, detonate objects and fry circuitry. By the time of the Ninth Doctor, the sonic was able to also be used as a sophisticated scanning device, with medical applications. Subsequent incarnations gave it even wider functionality, such as the ability to hack into computers, provide geolocation and actively defend against some types of assault weapons by frying their internal mechanics and causing the weapons to burst into flames and spark from the inside. The tool seemed to have electromagnetic properties and abilities, as it could be used to electrify the nervous system, and could create powerful frequencies and signals, as well as use sound to carry out its functions, even to the point where three of its latest incarnations where able to create a sonic force blast powerful enough to repel and destroy a Dalek while working together, as well as shoot green sonic energy waves to briefly incapacitate or stun a target.

All of these incarnations utilised the same software, though they used different cases. For all intents and purposes, the War Doctor's sonic was the same as the Eleventh Doctor's some 400 years later. (TV: The Day of the Doctor)

While almost always referred to as a sonic screwdriver, it has on occasion been referred to as a sonic probe by people other than the Doctor, such as Dalek Sec and a version of Amy Pond who had been stuck on Apalapucia for 36 years. The Tenth Doctor openly disliked this, and corrected those who did so. (TV: Doomsday, The Girl Who Waited)

Technology and functions
The sonic screwdriver was considered to be very advanced Gallifreyan technology. (PROSE: Heart of TARDIS)

The Doctor claimed that he either invented or designed the specific sonic screwdriver which he owned. When Kazran Sardick was confused as to what to do when it looked like Abigail Pettigrew was about to kiss him, the Eleventh Doctor told Kazran to trust him and kiss Abigail, as "It's this, or go to your room and design a new kind of screwdriver. Don't make my mistakes. Now, go." (TV: A Christmas Carol) When Captain Jack Harkness asked the Ninth Doctor, "Who looks at a screwdriver and thinks 'Ooh, this could be a little more sonic'?", the Ninth Doctor defensively responded, "What? You never been bored? Never had a long night? Never had a lot of cabinets to put up?" (TV: The Doctor Dances)

Other individuals had similar devices, such as the sonic pen used by Miss Foster (TV: Partners in Crime) and the sonic blaster used first by Captain Jack Harkness (TV: The Empty Child / The Doctor Dances) and later River Song. (TV: Silence in the Library / Forest of the Dead) Sarah Jane Smith had her sonic lipstick, (TV: Invasion of the Bane, et al.) and the Doctor himself once used a sonic cane. (TV: Let's Kill Hitler) Even Missy used a sonic umbrella. (TV: World Enough and Time/The Doctor Falls)

At least one version of the screwdriver used a crystal similar to the Metebelis crystal sought after by the Eight Legs of Metebelis III. (COMIC: The Forgotten) There were also electrical components. (COMIC: The Halls of Sacrifice)

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 Twelfth Doctor told Clara to use setting number 41 to send out random bursts of helicon energy to distract the Skovox Blitzer. (TV: The Caretaker) The Twelfth Doctor himself used setting sixty-one to knock out a cybernetically augmented dinosaur with a "sonic brainstorm". (COMIC: Spirits of the Jungle) However, at least one version of the screwdriver was able to use thoughts as well as settings. (TV: The Big Bang, Amy's Choice, Let's Kill Hitler, Death in Heaven)

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 (TV: The Empty Child) and repair of organic parts; (TV: The Vampires of Venice) cutting, but also re-attaching materials such as barbed wire; (TV: The Doctor Dances) operating Earth machinery such as computers (TV: School Reunion) and even cash machines (at regular and high eject speeds); (TV: The Runaway Bride) creating a spark to light a candle (TV: The Girl in the Fireplace) or Bunsen burner; (TV: Evolution of the Daleks) opening and holding doors with acoustic locks; (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, able to combine with other sonic devices to form a shield around a hostile target to either force them back or slow their advance. (TV: The Day of the Doctor, The Doctor Falls) 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 Silents 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) It could also destroy ice creatures when it received the latest update. (TV: The Snowmen)

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) The War Doctor claimed that it was a scientific instrument rather than a water pistol. (TV: The Day of the Doctor)

From time to time, the sonic screwdriver needed to be recharged. (TV: Silence in the Library / Forest of the Dead, PROSE: The Monsters Inside, COMIC: Bizarre Zero) It was self-repairing and could send out a homing signal to any parts that had been separated. (TV: A Christmas Carol) However, it was up to the owner to collect the parts for reassembly.

Sonic screwdrivers and similar technology could not unlock a deadlock seal. (TV: School Reunion, The Night of the Doctor) However, Miss Foster's sonic pen could open the deadlock seals that it was programmed to within her own facility when the Doctor's screwdriver could not. (TV: Partners in Crime) It also couldn't unlock the doors to the TARDIS if they had been manually locked at the console. (TV: Utopia) Some or all versions were ineffective against wood. (TV: Night Terrors, The Doctor, the Widow and the Wardrobe, The Time of the Doctor, Empress of Mars) It didn't work in the presence of some models of hairdryers, although the Tenth Doctor stated he was working on it. (TV: Forest of the Dead, PROSE: Catastrophea)

During his lifetime as the Twelfth Doctor, the Time Lord claimed to have abandoned sonic screwdrivers in favour of wearable technology like his sonic sunglasses. (TV: The Witch's Familiar, Under the Lake) However, after returning to Gallifrey and departing again, he resumed using them, as his TARDIS fashioned a new one for him as a gift. Furthermore, after the Doctor had lost sight of who he was, Clara Oswald left him a reminder to "be a Doctor" after leaving his company. As part of his role of being a Doctor to use a sonic screwdriver, the Doctor accepted the TARDIS's gift. (TV: Hell Bent)

The Doctor's screwdriver
The Doctor, throughout many of their lives, possessed a sonic screwdriver. They originally used a basic model in their first and second incarnations, before upgrading in their third. They continued to use this model until it was destroyed in their fifth by a Terileptil leader. It wasn't until they were in their seventh incarnation before they began to use a screwdriver again, taking on various different models throughout the years.

River's screwdriver
The Twelfth Doctor gave River Song's sonic screwdriver another screwdriver before River's final date with him at the Singing Towers of Darillium. (TV: The Husbands of River Song, Silence in the Library) This version of the sonic screwdriver somewhat resembled the Tenth Doctor's model when he met her at the Library, though it looked elaborately decorated and modified, featuring increased and enhanced functionality, including "dampers" and a "red setting" that allowed it to work without interference from the Doctor Moon. The Doctor gave it to River so she would be ready when she met his tenth incarnation in the Library. (TV: Forest of the Dead)

Other screwdrivers
Vastra had a sonic screwdriver that was a gift from the Doctor. She used it to shatter the glass of the Crystal Palace. It had a red tip, and was similar in design to that used by his eleventh incarnation. (COMIC: The Crystal Throne)

A clone of the Second Doctor also possessed a sonic screwdriver, which he used along with the Fourth Doctor's to send Hexford home. (AUDIO: Survivors in Space)

Romana II constructed her own sonic screwdriver. Her version was so impressive that the Doctor offered to swap sonic screwdrivers with her. (TV: The Horns of Nimon) Her version also included a silencer. (AUDIO: Luna Romana) She later gave it to the Doctor. (PROSE: Lungbarrow) Nonetheless, during the final term of her presidency, her third incarnation used a sonic screwdriver. (AUDIO: Intervention Earth)

Jackson Lake carried a primitive iteration of the sonic screwdriver. His version was a regular 19th century screwdriver, which he claimed was sonic by virtue of it making a sound when it was struck against a surface. (TV: The Next Doctor)

While trapped on Apalapucia for thirty-six years, Amy Pond cobbled together a sonic device from various pieces of technology, but insisted upon calling it a sonic probe. She later conceded that it was a "sonic screwdriver". (TV: The Girl Who Waited)

Behind the scenes
According to the non-fiction source REF: Doctor Who: The Visual Dictionary, which this wiki does not count as a valid source, a sonic screwdriver was a common and basic Time Lord device. If needed, a Time Lord could make one from scratch in very little time.