 :For other meanings, see Trigger (disambiguation). ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ In its earliest usage, trigger refers to a mechanical mechanism, the pulling or pushing of which sets a device into action. This includes the lever that sets off the chain of events that fires a gun, the release mechanisms on a crossbow, or the lever that engages an animal trap. ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ Today trigger is also used in a wider sense to refer to a precipitating cause of some event. The "trigger" (noun) is said to "trigger" (verb) the event. ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ Note that, in this wider sense, "trigger" need not be a necessary condition for the event. To the extent that it is a sufficient condition, this is only relative to some implied background conditions taken as given. (See necessary and sufficient conditions.) ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ Examples of triggers: ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ - If one adds a seed crystal to a supersaturated solution, the crystal will "trigger" the precipitation of the dissolved material.
- In the almost cliche idea of a butterfly flapping its wings and thereby causing a great weather disturbance (see chaos theory), the butterfly can be said to have "triggered" the disturbance.
- An event which causes an allergic reaction, for example, exposure to cat dander may trigger an asthma attack in an allergic person.
- A reminder in persons with post-traumatic stress disorder which can be either passive exposure to a specific visual/tactile/other sensual "image" resembling a part from the trauma experience, or an active body movement stored in procedural memory from the abusive 'training', which triggers the PTSD symptoms.
- In computer programming, software may be set up to be event driven, so that certain events (e.g. an insert, an update or a delete of a database) trigger the invocation of particular procedures. See Database trigger.
- In ethology, a trigger is a cue in the environment that causes the "release" of a (genetically predetermined) behavior. An example is the pecking behavior of young Herring gulls, elicited by a red spot on the beak of a parent. In this context, the trigger is also referred to as an eliciting stimulus.
- The use of the term trigger for oscilloscopes is explained in the relevant article.
- A Schmitt trigger is an electronic circuit.
- In business, a trigger point is a situation in which the level of stock holdings of a hostile bidder triggers anti-takeover provisions.
- In a particle physics detector, a trigger system uses simple criteria to rapidly decide which events to keep when only a few can be recorded. For an example of how this is integrated into a detector, see ATLAS trigger system.
- electronic drummers utilize piezoelectric transducers in trigger pads to produce waveforms in a sound module or a MIDI controller, which result in percussion instrument sounds.
Gun: A gun is a mechanical device that fires projectiles at high velocity, using a propellant such as gun powder or compressed air.... Crossbow: :This article is about the weapon crossbow. For alternate uses of the word crossbow, see Crossbow (disambiguation)... Animal trap: REDIRECT Animal trapping...
Trigger related Images and Photos (experimental) | 
