Sonic Screwdriver

The Sonic Screwdriver device was first shown on tv in the 1968 during the Patrick Troughton era. The Doctor produced it from his pocket to open a black metal box in episode one of Fury From The Deep (a serial now sadly missing from the archives). Troughton didn't rely on the sonic screwdriver as much as his successor, the gadget-loving Jon Pertwee.

The sonic screwdriver made its first appearance in the serial Fury from the Deep, written by Victor Pemberton. It was used thereafter by the Second Doctor as a multi-purpose tool, with occasional variations in appearance over the course of the series. Ownership of the concept was retained by the BBC; Pemberton later told an interviewer for Doctor Who Magazine, "I'm very cross that the sonic screwdriver—which I invented—has been marketed with no credit to myself. ... It's one thing not to receive any payment, but another not to receive any credit."

3rd Doctor

The third Doctor famously used the screwdriver to frighten away the eponymous creatures in The Sea Devils, by exploding mines along a beach.

During the Third Doctor's tenure, producer Barry Letts was adamant that the device not become a cure-all for the series, and limited its use to avoid writers becoming over-reliant on it. During this time, the device underwent significant design changes. In The Sea Devils, the Doctor used it to detonate landmines; Michael Bryant explains that this was feasible, stating that the sonic waves shook the mines. In The Three Doctors, a device which appears to be the sonic screwdriver is used to detect radiation, though in the DVD commentary, Letts remarks that it may have actually been a separate device.

4th Doctor

Fourth Doctor Tom Baker loved the idea that the sonic screwdriver (as a plot device) could open any door... except the ones that it couldn't! The mischievous Baker was keen to exploit the comedic potential of the prop. Indeed, at one point the Doctor breaks the ‘fourth wall' and addresses the audience in his frustration: "Even the sonic screwdriver won't get me out of this one..."

During the first three years of the Fourth Doctor's tenure, producer Philip Hinchcliffe further reduced the use of the sonic screwdriver. Exceptions include Robot, where it was again used to detonate mines, and as a "miniature sonic lance" to cut out a lock. Aside from unlocking doors, the device was greatly downplayed during the Fourth Doctor's second and third seasons. It saw a resurgence once Graham Williams took over as producer in 1977. In the final story of season 15, The Invasion of Time, the Fourth Doctor conceded, "Not even the sonic screwdriver can get me out of this one."

It featured regularly in season 16 during the Key to Time saga. The Doctor's Time Lady companion Romana constructed a sonic screwdriver of her own, first seen during the City of Death. It was smaller and sleeker than the Doctor's, and he was sufficiently impressed with her design that he attempted (unsuccessfully) to swap screwdrivers with her in Horns of Nimon. By season 18, both script editor Christopher Bidmead and producer John Nathan-Turner were eager to downplay the device as much as possible.

5th Doctor

Eighties Producer John Nathan-Turner decided the sonic screwdriver was too often used as a ‘magic wand' to solve any dilemma the Doctor faced. Keen to distance the show from magic, and in an effort to make the fifth Doctor more vulnerable, Nathan-Turner had the device written out. The sonic screwdriver was destroyed by the leader of the Terileptils in the 1982 Peter Davison adventure The Visitation, prompting the Doctor to mourn its passing: "I feel as though you've just killed an old friend..."

The sonic screwdriver was written out of the series late in season 19, in the Fifth Doctor serial The Visitation. It is destroyed by a Terileptil to prevent the Doctor from escaping a holding cell; in response, the Doctor remarked, "It feels like you just killed an old friend." Eric Saward later explained in a 2005 DVD interview[3] that this was done on the instructions of producer John Nathan-Turner. Saward had written out the sonic screwdriver, believing that the Doctor had "a cupboard full of them" in the TARDIS. On the basis that a device that could help in any situation was very limiting for the script, Nathan-Turner decided that it would not return. The Tenth Doctor joked about the Fifth Doctor's lack of sonic screwdriver in the mini-episode Time Crash, commenting that he "went hands-free" and could "save the universe using a kettle and some string." The device did not appear again for the remainder of the original series.

'You are a foolish man, Doctor,' the [Terileptil] Leader said, his eyes falling on the screwdriver. 'Drop the sonic device.'

[The Doctor] obeyed, sending the silver shape slithering across the floor. As it came to rest, the Leader fired, and the sonic screwdriver exploded, bursting into flames. The Doctor looked at the twisted strip of smoldering metal, unable to believe what he saw. 'I feel as though you've just killed an old friend.'

Doctor Who and the Visitation by Eric Saward

Castrovalva

The Doctor takes the screwdriver from the inside pocket of his new coat (did he put it there when he changed or was it always there?). Nyssa uses it to remove the doors from the Zero Room.

Four to Doomsday

The Doctor uses it to 'spin' the Monopticons. Nyssa uses it in conjunction with a pencil to deactivate some of the androids.

Kinda

Certain that he wouldn't need it, the Doctor uses the screwdriver as a power source for the Delta Wave Augmentor he builds to help Nyssa sleep.

The Visitation

It is used to open the sonic barrier under the Squire's house. Later, the Terileptil Leader destroys it.

Snakedance

Nyssa wishes they still had the screwdriver so that she and the Doctor could escape from their cell.

Although the sonic screwdriver had been destroyed there were plans to bring it back during the sixth Doctor's era. In a 1984 interview, JNT said the sonic screwdriver might return but it would be a lot more sophisticated. Indeed, in Graham Williams' novelisation of his aborted season 23 story The Nightmare Fair the Doctor produces the sonic screwdriver while locked up in a dungeon (although this could simply be ignorance on Williams' part, and he wasn't aware that the tool had been destroyed). The most recent mention of the device is in Terrance Dicks' 1991 book Timewyrm: Exodus; the Doctor searches his pockets wondering what he has done with it (p.180). From this it would appear that the Doctor has built himself a new one after all!

In the mid-1980s the American company Spirit of Light produced a battery operated plastic version of the screwdriver, which cost about 14 pounds in Britain. The toy was capable of 'buzzing' just like the real thing, and that was about all it could do!

Finally, the 1983 Doctor Who Technical Manual contains diagrams of the screwdriver. Unfortunately the measurements given are in centimetres instead of millimetres giving the impression that the sonic screwdriver is two metres long! Try fitting that into your pocket, Doctor!

Doctor Who Movie (1996)

In the 1996 Doctor Who TV movie, seventh Doctor Sylvester McCoy finally managed to get his hands on a restored sonic screwdriver, albeit in his swansong as the Timelord. Paul McGann's Doctor only got the sonic screwdriver back at the end of the film and used it to repair the TARDIS console.

In the 1996 Doctor Who TV Movie, the Doctor was seen to have a new sonic screwdriver with a telescopic design.

New Series

When the show was re-imagined by Russell T. Davies, the sonic screwdriver made a welcome return and, perhaps with an eye to the inevitable merchandising, it was redesigned and improved.

A redesigned sonic screwdriver appears in the new series, with a blue light in addition to the sound effect. In its first incarnation, the prop used in the new series was fragile and prone to breakage. The toy version (made by Character Options Ltd.) was slightly larger to accommodate a pen (with swappable standard and ultraviolet ink nibs) and batteries. It also includes an ultraviolet light for viewing messages written in the ultraviolet ink. The Doctor Who production team at BBC Wales were so impressed by how much more resilient the toy sonic screwdriver was than the real prop, that they obtained moulds of the original prototype of the toy to use in the 2006 series.

In contrast with Nathan-Turner's attitude that the sonic screwdriver should not be used as a cure-all, the new production team gave it even more functionality than previous versions. Some of the uses in the new series include: repairing electronic equipment; detecting, intercepting and sending signals; remotely operating the TARDIS; burning, cutting, or igniting substances; fusing metal; scanning and identifying substances; amplifying or augmenting sound; modifying mobile phones to enable "universal roaming”; disabling alien disguises. It is sometimes used to disassemble robotic enemies or turn other objects into weapons; healing cuts and wounds. In "The Long Game", "The Parting of the Ways" and "Utopia" it is used to operate the TARDIS controls remotely; when the Doctor attempts to counteract the Master's theft of the TARDIS, it is used to limit the TARDIS' destination. In "Doomsday", the Doctor states that the sonic screwdriver does not kill, wound or maim; however, it is sometimes brandished in a threatening manner, such as in "The Christmas Invasion", "The Runaway Bride", "The Lazarus Experiment", The Infinite Quest and The Impossible Planet. In "World War Three", when confronted by a group of Slitheen, the Doctor threatens to "triplicate the flammability" of a bottle of port wine with the sonic screwdriver, though one of the Slitheen realises he is bluffing.

The sonic screwdriver has been the subject of jokes: in "The Doctor Dances", Jack Harkness mocked the concept by asking, "Who looks at a screwdriver and thinks, 'Ooh, this could be a little more sonic'?", and later exclaims to the Doctor that "in a pinch, you could put up some shelves!" In "Smith and Jones", Martha Jones asked if the Doctor also had a "Laser Spanner", to which he replied that he had, until it was stolen by Emmeline Pankhurst.

In "Smith and Jones", the sonic screwdriver burns out after the Doctor uses it to amplify the radiation output of a hospital X-ray machine. In the "Series Three concept Artwork Gallery", when referring to the burnt out sonic screwdriver, Peter McKinstry says "the green crystal structure visible under the shattered dome refers back to the TARDIS console crystal. It's the same technology - the TARDIS's little brother." Though initially saddened at the loss of the screwdriver, the Doctor obtains a new one at the conclusion of the episode.

In "The Eleventh Hour", the malfunctioning sonic screwdriver is destroyed when the Doctor tries to signal the Atraxi ships. The Doctor later receives a new one, which emerges from the newly-regenerated TARDIS console. The Eleventh Doctor's sonic screwdriver is larger than its predecessor; it has a green light and metal claws that extend with a flick of the wrist. A toy version of this (also by Character Options) is available.

11th Doctor

 If you follow Dr Who then you will have noticed he got both a new TARDIS and a new Sonic screwdriver. The Eleventh Doctor's Sonic Screwdriver. Considerably bigger than the 9/10th Doc's one

Limitations
The sonic screwdriver is unable to open a "deadlock seal", used as a plot device to prevent an easy solution. In "Silence in the Library", while trying to open a wooden door, the Doctor tells Donna that the sonic screwdriver won't work because the door is made of wood. In the same episode, the Doctor mentions that when Emergency Program One was activated, the sonic screwdriver would receive a signal from the TARDIS. In the following episode, "Forest of the Dead", he claims that a few hair-dryers can interfere with the device, though he states that he is "working on that". In "The Hungry Earth", the Doctor says to Rory that it doesn't work on wood.
 

Laser Screwdriver

The sonic screwdriver even has its own imitators in the form of The Master's laser screwdriver seen at the end of series three and Sarah Jane Smith's sonic lipstick in the spin-off Sarah Jane Adventures.

Other Sonic Screwdrivers

Two characters in series four, Miss Foster and River Song had their own sonic screwdrivers.

In "The Sound of Drums", the Master reveals his laser screwdriver. Unlike the sonic screwdriver, it is used as a weapon that can kill as well as artificially age its target, using technology developed by Lazarus Laboratories originally seen in "The Lazarus Experiment". It includes isomorphic controls, allowing only the Master to use the device. The design of the prop was meant to imply that the Master constructed it on Earth, and it was deliberately made larger than the Doctor's sonic screwdriver.[7] Like the Doctor's screwdriver and Sarah Jane's lipstick, the Master's laser screwdriver was also created as a children's toy with sound effects.
In the series 4 episode "Partners in Crime", the antagonist Miss Foster is shown using a sonic device identified by her as a sonic pen, which the Doctor describes as having identical functionality to his screwdriver. After confiscating and briefly using it, the Doctor throws the sonic pen into a bin.
In "Silence in the Library", Professor River Song possesses a slightly bulkier sonic screwdriver, which she claims the Doctor gave to her in his future. The Doctor mentioned that he does not give his screwdriver to anyone. In the following episode, Professor Song mentions that her screwdriver is augmented with a "red setting" and "dampers". It also contains a hidden neural relay linked to River Song, saving her at the episode's conclusion—the purpose for which the future Doctor gave Professor Song the device. A toy version is available.
In the Christmas special The Next Doctor, Jackson Lake, who believes himself to be the Doctor, carries a regular screwdriver which he claims to be sonic. When the Doctor asks "How is it sonic?", Lake replies, "It makes a noise," which he demonstrates by tapping it against a door frame.

Arguably, David Tennant's Doctor uses the sonic screwdriver more than any of his predecessors, especially in the BBC books and audios where it is often annoyingly referred to as "the sonic". Clearly it has become an essential tool all over again.

So, despite the best efforts of the Terileptils over a quarter of a century ago, the sonic screwdriver lives on. Whether it will be a ‘weapon of choice' for upcoming Doctor, Matt Smith, remains to be seen, but it is undoubtedly one of the great iconic motifs of the series.

In the Doctor Who spin-off series, The Sarah Jane Adventures, Sarah Jane Smith uses a "sonic lipstick", which is a gift the Tenth Doctor gave her alongside a new model of K-9 and her scanner watch. It functions much like the sonic screwdriver, used primarily for opening and closing locked doors.

Uses

The sonic screwdriver is apparently the product of Gallifreyan technology since other Time Lords (i.e. Romana) used the device and understood it enough to construct their own versions of it. The name of the device itself suggests that it functions using soundwaves, although the actual workings of the device have never been explained.

A crystal similar to Metebelis Crystal sought after by the Eight Legs of Metebelis III was used in the Mark VI sonic screwdriver. (IDW: The Forgotten)

The screwdriver also seems to have a multitude of settings, along with different versions of settings, as he tells Rose to use "setting 15B" to help him triangulate the source of the ghosts (DW: Army of Ghosts) and it is said to have a setting 85. (DW: The Lazarus Experiment). The Doctor tells Rose to use setting 2428D to re-attach barbed wire, suggesting that the screwdriver (at least the Mark V screwdriver) has at least this many functions. (DW: The Doctor Dances)

The different versions of the Doctor's sonic screwdrivers have exhibited different capabilities and uses, such as the interception of signals ranging from transmat beams to conscious thought; medical diagnostics and repair of organic parts; cutting, but also re-attaching together materials such as barbed wire; operating Earth machinery such as computers and even cash machines (at regular and high eject speeds); creating a spark to light a candle; and, on the rare occasion, driving screws without touching them. Although it is primarily a tool, it can also be used as a defensive weapon, such as when the Tenth Doctor put it in a sound board to destroy the Robot Santas. (DW: The Runaway Bride) However, according to the Tenth Doctor, the device cannot be used to wound, maim or kill living things. (DW: Doomsday) It can still be used to destroy non-living objects or mechanisms or place living creatures in circumstances where they might die, if the situation requires.

The sonic screwdriver needed to be recharged, (NSA: The Monsters Inside) which was likely done by the TARDIS (DW: Aliens of London, The Eleventh Hour)

Sonic screwdrivers and similar technology cannot unlock a deadlock seal (DW: School Reunion); one of few exceptions is Miss Foster's sonic pen, which was able to open the deadlock seals on and within the Adipose Industries building when the Doctor's sonic screwdriver could not. (DW: Partners in Crime) Some or all versions may be ineffective against wood, or in the presence of some models of hairdryers. (DW: Silence in the Library / Forest of the Dead,The Hungry Earth, PDA: Catastrophea)

In DW: Aliens of London the Doctor's sonic screwdriver is seen standing upright on the TARDIS console. This suggests that the TARDIS may charge the sonic screwdriver. This means that the sonic screwdriver may have a battery supply of some sort. However, with the revelation in DW: The Eleventh Hour that the TARDIS itself can manufacture screwdrivers, that this recess may simply be the equivilant of a tool holder or fabrication station. In NSA: "The Monsters Inside" the sonic screwdriver needs charging. This may mean the TARDIS creates, stores and charges sonic devices.

Variants of the Sonic Screwdriver

Mark IA small, simple device similar to a penlight, first used by the Doctor in his first (MA: Venusian Lullaby) and second incarnations (DW: Fury from the Deep).

Known usesCracking the code for an aerodynamic shuttle. (MA: Venusian Lullaby).
Opening up hatches, panels and control panels. (DW: Fury from the Deep, The War Games)
For cutting through a section of a wall. (DW: The Dominators)
As a conventional screwdriver (without touching the screws). (DW: The War Games)

Mark II

A larger and more elaborately detailed version, the Doctor began using this model in his third incarnation. In addition to a redesign on the tip which remained the norm for the next two versions, it had a silver handle, and black and yellow stripes. It had a removable head which the Doctor would change with other heads, each doing a different function. (DW: The Sea Devils)

Known uses

To remotely open his workshop. (DW : Inferno)
Booby trap detector in the Master's TARDIS. (DW: Colony in Space)
Remote detection and detonation of land mines. (DW: The Sea Devils)
To open an electronic door. (DW: The Mutants)
Undoing wrist clamps. (DW: The Mutants)
Creation of a spark of fire and igniting swamp gas. (DW: Carnival of Monsters)
Open electronic locks. (DW: Carnival of Monsters)
As conventional screwdriver, on large, flathead screw. (DW: The Monster of Peladon)
To distract giant maggots. (DW The Green Death)

Mark III

The Fourth Doctor remade his sonic screwdriver into a silver version that lacked the interchangeable heads. It was capable of extending its tip.

Known usesRemotely detonating mines. (DW: Robot)
Cutting locks. (DW: Robot)
Fixing a circle of transmat refractors. (DW: The Sontaran Experiment)
Breaching a force field. (DW: The Sontaran Experiment)
Shutting down Styre's Robot. (DW: The Sontaran Experiment)
Sabotaging a two-way radio. (DW: Genesis of the Daleks)
Creating a temporary hole in Gallifrey's force field above the Citidel. (DW: The Invasion of Time)
Using the correct sonic frequency to return The Doctor and Ernestina Stott to normal size. (BBCR: Hornets' Nest - The Dead Shoes)
Opening doors on Ribos. (DW: The Ribos Operation)
Unlocking multi-levered interlocks to the Ribos crown jewels casket (DW: The Ribos Operation)
Opening the door to the real Queen Xanxia's camber. (DW: The Pirate Planet)
Blowing up a Dalek bomb. (DW: Destiny of the Daleks)
Mark IV
Chang Lee discovers the sonic screwdriver the Seventh Doctor had at regeneration. (DW: Doctor Who)Towards the end of his Seventh Incarnation The Doctor used a model quite simillar to his Mark III exept that instead of the ring around the tip being red, the tip it self was red. This is used throughout the Eighth Doctor's life and has a torch built in the handle.

To lock the casket containing the Master's remains. (DW: Doctor Who)

Mark V

In his ninth incarnation the Doctor had a new model with a glowing blue diode at one end. The tenth incarnation of the Doctor also carried this model, until it was burnt out after modifying an x-ray scanner to increase the radiation output. (DW:Smith and Jones)

Known uses

To destroy the controls of an elevator. (DW: Rose)
Detecting and stopping telepathic signals. (DW: Rose)
Interfacing with a computer. (DW: The End of the World)
To control an elevator. (DW: Aliens of London)
As a medical scanner and diagnostic tool. (DW: The Empty Child)
Obtaining money from a cash machine. (DW: The Long Game)
Battery charging. (DW: Father's Day)
Completely corroding thin metal (e.g. barbed wire) so that it crumbles into rust. (DW: The Doctor Dances)
Re-connecting barbed wire. (DW: The Doctor Dances)
Unlocking handcuffs. (DW: The Doctor Dances)
Setting up a resonation pattern in concrete. (DW: The Doctor Dances)
Reversing teleport devices. (DW: Boom Town)
To destroy a television camera. (DW: Bad Wolf)
Dematerialising the TARDIS and initialising TARDIS processes from outside the craft. (DW: The Parting of the Ways)
Blowing up a remote control Christmas tree. (DW: The Christmas Invasion)
To transfer its powers to a remote control. (DW: Attack of the Graske)
To create small flames. (DW: The Girl in the Fireplace)
To make the Cybermen turn away from the Doctor's direction. (DW: The Age of Steel)
To cut rope. (DW: The Age of Steel)
Locking / unlocking a hatch in Cybus Industries (DW: The Age of Steel)
To threaten the Wire. (DW: The Idiot's Lantern)
To partially reverse the Abzorbaloff's absorption of Ursula Blake. (DW: Love & Monsters)
Partially cracking glass so it can be smashed with the push of a finger. (DW: Army of Ghosts)
Detonation of an explosive device. (DW: Doomsday)
Get money from cash machine, at both regular and extra-high rates of ejection. (DW: The Runaway Bride)
To unlock a taxi door and window. (DW: The Runaway Bride)
Scan a lifeform for information, specifically Donna Noble. (DW: The Runaway Bride)
To detonate the head of a roboform (DW: The Runaway Bride)
Search a phone for an app or a feature. (DW: The Runaway Bride)
Hacking into the HC Clements website. (DW: The Runaway Bride)
Bypass the key needed to access the secret basement in HC Clements. (DW: The Runaway Bride)
Able to summon the Tardis using Huon particles. (DW: The Runaway Bride)
To cut a spider web. (DW: The Runaway Bride)
To destroy the Robot Santas with sound (used in conjunction with a professional sound system). (DW: The Runaway Bride)
To increase the radiation output of a device such as an x-ray scanner; this action burned out the screwdriver. (DW: Smith and Jones)

Mark VI

The tenth incarnation used another screwdriver after the X-ray incident. This model was damaged during the Doctor's tenth regeneration and the TARDIS' subsequent crash, as well as by Prisoner Zero and was ultimately destroyed when the Doctor used it to overload technology to alert the Atraxi. (DW:The Eleventh Hour)

Known uses

Opening air tight seals. (DW: Gridlock)
Trying to strip off pieces of Dalekanium. (DW: Evolution of the Daleks)
Lighting a bunsen burner from a distance. (DW: Evolution of the Daleks)
Bypassing and turning off security systems. (DW: The Lazarus Experiment)
In conjunction with a pipe organ, it produced hypersonic sound waves which lead to the death of the Lazarus creature. (DW: The Lazarus Experiment)
Scanning for the transformed Lazarus creature after it escaped to Southwark Cathedral. (DW: The Lazarus Experiment)
Locking the TARDIS navigational systems to only allow travel between its current position and its previous position. (DW: Utopia)
Fixing a decades-broken Vortex Manipulator. (DW: Utopia)
To destroy a security camera. (DW: The Sound of Drums)
As a soldering iron to make perception filters using TARDIS keys. (DW: The Sound of Drums)
Uncorking a wine bottle. (DW: Voyage of the Damned)
Controlling a cable cart. (DW: Partners in Crime)
Breaking into a silo on the Ood-Sphere. (DW: Planet of the Ood)
Disabling a Sontaran teleport. (DW: The Sontaran Stratagem)
Scanning shadows for the presence of Vashta Nerada. (DW: Silence in the Library/Forest of the Dead)
Showing a hologram of Donna Noble. (DW: Forest of the Dead)
Tinting a Helmet Visor (DW: Forest of the Dead)
Disabling the Crusader 50's entertainment system. (DW: Midnight)
Checking Crusader 50's control console for faults. (DW: Midnight)
Teleporting a Graske to the other side of the universe. (DW: Music of the Spheres)
As a Sonic Toothbrush. (DWAM: The Continuity Cap)
Tickling a lion with sonic waves. (NSA: The Slitheen Excursion)
Tinting the Doctor's glasses. (DW: Planet of the Dead)
Opening bus doors. (DW: Planet of the Dead)
Unlocking handcuffs. (DW: Planet of the Dead)
Cracking ice. (DWAM: Arctic Eclipse)
Detecting time traces. (SJA: The Wedding of Sarah Jane Smith)
As an actual Screwdriver, without touching the screws. (DW: Dreamland)
Disabling a Shimmer. (DW: The End of Time)
Switching the Hesperus' power off. (DW: The End of Time)
Changing the course of the TARDIS. (DW: The Eleventh Hour)
Opening a "crack" in space-time. (DW: The Eleventh Hour)
Overloading all technology in an area (To the point where the screwdriver itself explodes). (DW: The Eleventh Hour)
Mark VII

Known UsesScanning Starship UK's engine room. (DW: The Beast Below)
As a torch. (DW: The Beast Below)
To force a Star Whale to regurgitate by overloading its chemo-receptors. (DW: The Beast Below)
Making a Star Whale's voice audible to the human ear. (DW: The Beast Below)
Amplifying an electrical beam. (DW: The Beast Below)
Opening the chest plate of an Android's controls, (unsuccessfully) attempted to defuse the bomb inside it. (DW: Victory of the Daleks)
To increase a signal strength. (DW: The Time of Angels)
To scan Father Octavian's computer. (DW: The Time of Angels)
To open a mechanical door (unsuccessful when combating the Weeping Angels). (DW: The Time of Angels)
Opening the entrance hatch of a space ship. (DW: Flesh and Stone)
Isolating the lighting so that the Weeping Angels could not drain the power. (DW: Flesh and Stone)
Redirecting all the power to the doors in order to open them. (DW: Flesh and Stone)
Determining the nature of the cracks throughout time and space. (DW: Flesh and Stone)
To send a signal through to Amy's communicator to help guide her to the right spot in the forest in order to teleport her. (DW: Flesh and Stone)
Uploading software. (DW: Flesh and Stone)
Simultaneously healing and analysing wounds. (DW: The Vampires of Venice)
Sealing doors. (DW: The Vampires of Venice)
To open gates. (DW: The Vampires of Venice)
Block out the effects of perception filters. (DW: The Vampires of Venice)
Detecting where lights are. (DW: Amy's Choice)
Exploding lightbulbs. (DW: Amy's Choice)
Scanning lifeforms. (DW: Amy's Choice)
Scanning piles of dust for traces of children. (DW: Amy's Choice)
Unlocking padlocks. (DW: The Hungry Earth)
Hacking into computer records. (DW: The Hungry Earth)
Displaying energy barricades which are usually invisible to the naked eye. (DW: The Hungry Earth)
Activating Bio-programmed soil. (DW: The Hungry Earth)
Scanning for heat signatures. (DW: Cold Blood)
Disabling Silurian weapons. (DW: Cold Blood)
Scanning an infection. (DW: Cold Blood)
Locking the TARDIS doors. (DW: Cold Blood)
Opening the gate to the London Underground. (VG: City of the Daleks)
Opening up a discarded Dalek dome. (VG: City of the Daleks)
Bypassing Dalek security seals. (VG: City of the Daleks)
Opening up control panels in Kaalann. (VG: City of the Daleks)
Accessing the Visuliser eye. (VG: City of the Daleks)
Tampering with The Dalek Emperor's casing. (VG: City of the Daleks)
Activating a Dalek console trap. (VG: City of the Daleks)
Restoring the Visuliser eye's power. (VG: City of the Daleks)
Constructing a Dalek Vision Disruptor. (VG: City of the Daleks)
Opening Kaalann doors. (VG: City of the Daleks)
Heating Water and Ice. (VG: Blood of the Cybermen)
Giving a Cybermat a "Cyber-Migrain". (VG: Blood of the Cybermen)
Distracting Cybermats. (VG: Blood of the Cybermen)
Fixing platform lift control panels. (VG: Blood of the Cybermen)
Closing the door to the Cyber-conversion chamber. (VG: Blood of the Cybermen)
Unlocking Cyber-conversion unit manacles. (VG: Blood of the Cybermen)
Unsuccessfully attempting to stun the Krafayis (possibly due to being unable to find the right prozactic setting), appearing to please it instead. (DW: Vincent and the Doctor)
Opening the door to the Attempted TARDIS. (DW: The Lodger)
Scanning Stonehenge. (DW: The Pandorica Opens)
Lighting flaming torches. (DW: The Pandorica Opens)
Scrambling a Cyberarm's circuits. (DW: The Pandorica Opens)
Scanning the Pandorica. (DW: The Pandorica Opens)
To open the Pandorica (DW: The Big Bang)
Locking the National Gallery's doors. (DW: The Big Bang)
Amplifying a satellite dish to scan for an exploding TARDIS. (DW: The Big Bang)
Locking the National Gallery's roof hatch. (DW: The Big Bang)
 

Mark ?
The Doctor's future screwdriver, loaned out to River Song. (DW: Silence in the Library/Forest of the Dead)
A cross-section of the future sonic screwdriverIn the Doctor's personal future, he would upgrade the screwdriver with, in addition to the Mark VI settings, red settings and damper settings. He gave it to River Song, both for her use and, unknown to River, a Neural Relay, which saved River's Data Ghost for uploading into the main computer of the Library. (DW: Silence in the Library / Forest of the Dead)

Known uses

Related ToolsLiz Shaw had her own version of the Doctor's "door handle" device, which she used to open the door to the Doctor's shed. (DW: Inferno)
Romana constructed her own sonic screwdriver. Her version so impressed the Doctor that he attempted (unsuccessfully) to swap sonic screwdrivers with her. (DW: The Horns of Nimon) She later gave it to the Doctor. (NA: Lungbarrow)
This resembled a smaller, slimmer version of the Doctor's Mark II.
The Master had a similar tool called a laser screwdriver. (DW: The Sound of Drums)
Captain Jack Harkness and later River Song possessed a sonic blaster. (DW: The Empty Child/The Doctor Dances, Silence in the Library/Forest of the Dead)
Using stolen and incomplete UNIT design plans, Toshiko Sato created a sonic modulator. (TW: Fragments)
Miss Foster had a sonic pen, with a similar design, described as sleek, to the Doctor's sonic screwdriver. (DW: Partners in Crime)
The Doctor gave Sarah Jane Smith a sonic lipstick, a similar tool. (SJA: Invasion of the Bane)
The Doctor mentions that he once had a laser spanner as well but Emmeline Pankhurst took it from him. (DW: Smith and Jones)
Mrs Wormwood was in possession of a ring called a Phonic disruptor. (SJA: Enemy of the Bane)
The Sixth Doctor defeated Cybermen using a sonic lance, similar in function but designed to work as a weapon as well. [source needed]
Jackson Lake carried what is most likely the most primitive iteration of the sonic screwdriver. His version was a regular 19th century screwdriver which he claimed to be sonic by virtue of it making a sound when it was hit against a surface. (DW: The Next Doctor)

Related Tools

Liz Shaw had her own version of the Doctor's "door handle" device, which she used to open the door to the Doctor's shed. (DW: Inferno)
Romana constructed her own sonic screwdriver. Her version so impressed the Doctor that he attempted (unsuccessfully) to swap sonic screwdrivers with her. (DW: The Horns of Nimon) She later gave it to the Doctor. (NA: Lungbarrow)
This resembled a smaller, slimmer version of the Doctor's Mark II.
The Master had a similar tool called a laser screwdriver. (DW: The Sound of Drums)
Captain Jack Harkness and later River Song possessed a sonic blaster. (DW: The Empty Child/The Doctor Dances, Silence in the Library/Forest of the Dead)
Using stolen and incomplete UNIT design plans, Toshiko Sato created a sonic modulator. (TW: Fragments)
Miss Foster had a sonic pen, with a similar design, described as sleek, to the Doctor's sonic screwdriver. (DW: Partners in Crime)
The Doctor gave Sarah Jane Smith a sonic lipstick, a similar tool. (SJA: Invasion of the Bane)
The Doctor mentions that he once had a laser spanner as well but Emmeline Pankhurst took it from him. (DW: Smith and Jones)
Mrs Wormwood was in possession of a ring called a Phonic disruptor. (SJA: Enemy of the Bane)
The Sixth Doctor defeated Cybermen using a sonic lance, similar in function but designed to work as a weapon as well. [source needed]
Jackson Lake carried what is most likely the most primitive iteration of the sonic screwdriver. His version was a regular 19th century screwdriver which he claimed to be sonic by virtue of it making a sound when it was hit against a surface. (DW: The Next Doctor)

Behind the scenes

The tool was retired during the Fifth Doctor serial The Visitation as it was felt it had become overused. It was absent for the Sixth Doctor era and all of the Seventh, except in Doctor Who in which the Seventh Doctor was seen to use it to lock the Master's remains away, and the Eighth Doctor recovered it at the end of the film. The tool was reintroduced with the Ninth Doctor and has become the show's most frequently used gadget besides the TARDIS itself. It has since appeared in many Seventh and Eighth Doctor audio adventures from Big Finish Productions.
For unexplained reasons, the Tenth Doctor's Sonic Screwdriver had a green casing in The Infinite Quest.
During early production of Series 1 (2005), the production crew decided to switch from their original prop to one based on the toy Sonic Screwdriver because the first prop was prone to falling apart and so the production team secured molds from the toy replica in order to make a more reliable prop for the next season.
Early conceptual art of the modern era Sonic Screwdriver feature a different "tube" section, with notes referring to "glowing organic circuitry", and a movable ball-joint on the emitter, to allow use around corners and in tight spaces. Instead of the "glowing circuitry," the actual prop and toy reproductions feature a black "swivel," like a simple helix. When given a personal copy of the concept art, David Tennant himself commented on the lack of the swivelling emitter.
Another early piece of concept art, similar to a simple Bitmap drawing, reveals that the black "cap" at the reverse end of the Sonic Screwdriver was intended to be an opening set of "feet," allowing the Sonic Screwdriver to plug into a section of the TARDIS console. This feature was also dropped from the eventual prop model. The "claws" on the Series 5 model of the sonic screwdriver may be a re-imagining of these "feet".
There are two main versions of the Sonic Screwdriver - one has a slide feature with button, and one which does not slide and has a fixed button. The two prop types varied each episode.