Multiple realities
(covers information from several alternate timelines)

A beam setting was the amount of discharge given-off by a directed energy weapon, such as phase-pistols, plasma rifles, phasers, or disruptors. It was similar in concept to the variable yield capability used on torpedoes.

When Spock, Data, and Jean-Luc Picard outmaneuvered Sela in her office, Spock held a captured Romulan disruptor to her and warned her "I'm afraid I don't know too much about Romulan disruptor settings," forcing her to surrender. (TNG: "Unification II")

Stun setting

Captain Jean-Luc Picard shows Q a type 1 phaser set to stun

"Keep your phasers on stun. And stay calm. I don't want anyone getting nervous and shooting one of us by mistake."

The stun setting was non-lethal, low yield beam setting; powerful enough to cause disorientation, unconsciousness, and minor skin burns to a humanoid lifeform. (TOS: "The Man Trap"; TNG: "Samaritan Snare"; VOY: "Distant Origin") While relatively benign to a humanoid, some stun settings could cause smoke, sparks, electromagnetic discharge, or any combination of the above to be emitted from walls and other solid surfaces and objects the beam struck. (ENT: "Damage"; TNG: "First Contact")

Romulan disruptors had no stun setting, and nor did at least some 22nd century Andorian weapons. (PIC: "The End is the Beginning"; ENT: "Cease Fire")

There were many resilient species against which the stun setting had little or no effect, including Augments, (Star Trek Into Darkness) the Xindi-Reptilians, (ENT: "Carpenter Street") and Humans infected by a parasitic being. (TNG: "Conspiracy") Angosians who had undergone conditioning to fight in the Tarsian War were also largely unaffected by the stun setting. (TNG: "The Hunted") To some more vulnerable species, even the stun setting was potentially lethal, for example the Trill symbionts. (DS9: "Invasive Procedures") When used at close range, a phaser set on stun was capable of inducing sufficient trauma to kill a Human, if fired at a vital organ such as the brain. (Star Trek VI: The Undiscovered Country)

Phase-pistols in use by Starfleet in the 2150s featured stun as one of two settings, the other being kill. (ENT: "Broken Bow", "Terra Nova") Their stun setting could also be used to ignite fires. (ENT: "Desert Crossing") Later Starfleet phasers in the 23rd and 24th centuries had several different levels of stun setting. Starfleet regulations stated that phasers were to be locked at the level one stun setting. (TNG: "Aquiel")

A phaser set to stun could render a Human female unconscious in 0.9 seconds, something that was of no use to Miles O'Brien when a Pah-wraith possessed his wife, as it was still more than enough time for the Pah-wraith to kill her. (DS9: "The Assignment")

In an ultimately omitted scene extension from the script of TOS: "Court Martial", Spock gave Captain Kirk a phaser just before Kirk left the bridge of the USS Enterprise in order to search the ship for Benjamin Finney, who Spock speculated might already be armed. Though Kirk checked the phaser and started to make an adjustment on it, Spock notified him the weapon was already on the stun setting, for which Kirk was thankful.

Levels of stun

Pakleds stun Geordi La Forge with a Starfleet phaser

  • A higher stun setting caused a brief moment of unconsciousness to most humanoids. Although mostly harmless when used at this setting, multiple phaser stuns like this could culminate in serious injury to the central nervous system, and, after multiple hits, death. (TNG: "Samaritan Snare")
According to the Star Trek: The Next Generation Technical Manual (pp. 135 & 136), the first three settings on Starfleet phasers were the light, medium and heavy stun. According to the Manual, setting 1 was designed to only cause disorientation, setting 2 unconsciousness for fifteen minutes and setting 3 unconsciousness for an hour.

Modifications

In a similar way as the kill setting could be used to quickly kill a room full of people when set on a wide beam setting (VOY: "Worst Case Scenario"), a wide-field stun setting could be used to stun large groups with a single shot. (TOS: "The Return of the Archons"; TNG: "Power Play")

Along with hand weapons, shipboard phaser banks could be modified to deliver a potent stunning beam to incapacitate large crowds on the surface of a planet, when fired from orbit. (TOS: "A Piece of the Action")

Kill setting

Mordanite soldier firing a phaser set to kill

The kill setting was a yield setting that was intended to cause death to a humanoid lifeform. (ENT: "Broken Bow", "Cease Fire"; DS9: "Second Skin")

On a type 2 phaser used by the Starfleet in the 23rd century, "one-quarter" and "force 3" were other terms for the kill setting. In the 24th century, the setting was known as "level 10". (TOS: "The Man Trap", "Operation -- Annihilate!"; TNG: "Aquiel")

Yield

On phase-pistols used by Starfleet personnel in the mid-22nd century, the kill setting was the normal maximum setting, and was rated at a yield of five megajoules. (ENT: "Broken Bow", "Regeneration")

Cardassian phase-disruptor rifles were also similarly designed with only two settings and the maximum yield of 4.7 megajoules. (DS9: "Return to Grace")

The impact of a phaser or a disruptor blast set to kill left behind an electrostatic charge. (DS9: "Second Skin") A phaser set to kill also left behind a distinct phaser burn on clothing. In 2370, Jason Vigo suggested to Bok that he could create such a phaser burn on his shirt and send it to Captain Jean-Luc Picard, to try to convince him that Bok had killed him. (TNG: "Bloodlines")

Applications

Andorian rifles were set to kill by default and had no stun setting

Andorian rifles used by the Andorian Imperial Guard in the mid-22nd century were set to kill by default; they had no stun setting. (ENT: "Cease Fire")

When a phase-pistol set to kill only grazed a target, it was possible to survive from the hit. (ENT: "United")

In 2267, the kill setting was found to be non-lethal to the flying parasites that invaded Deneva. Because each parasite was part of a huge organism, and drew strength from that organism, it could resist extended exposure to a hand phaser set to kill. Parasites exposed for five to ten seconds reacted as if mildly stunned; they fell from the surface to which they were attached, and did not react to external stimuli for about a minute. (TOS: "Operation -- Annihilate!")

The kill setting on hand phasers used by the Mordanites in 2364 had a distinct sound from the stun setting. (TNG: "Too Short a Season")

To a Human infected by a parasitic beings, the kill setting only caused unconsciousness, due to the high levels of adrenaline stimulated by the parasite. However, extended exposure to a body part such as the head of a humanoid would still cause it to explosively vaporize. Two phasers set to kill could also vaporize smaller lifeforms such as the neural parasite mother creature with extended exposure. (TNG: "Conspiracy")

In 2366, Commander William T. Riker of the USS Enterprise-D was forced to use his phaser to disintegrate the Acamarian servant girl Yuta to prevent her from killing the Lornak tribe leader Chorgan. Stun and kill settings only caused her to recoil in pain due to her genetic enhancements. (TNG: "The Vengeance Factor")

See also

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