From Longman Dictionary of Contemporary Englishactivateac‧tiv‧ate /ˈæktɪveɪt/ verb [transitive] technical SWITCH ON OR OFFto make an electrical system or chemical process start working OPP deactivate Cooking fumes may activate the alarm. The yeast’s growth is activated by sugar and warmth. —activation /ˌæktəˈveɪʃən/ noun [uncountable]RegisterIn everyday English, people usually use set off rather than activate when talking about electrical systems:Someone has set off the smoke alarm again.→ See Verb table
Examples from the Corpus
activate• The bomb's firing mechanism is activated by a time-clock.• The manufacture of chlorophyll in plants is activated by sunlight.• The process is activated by sunlight.• Melanin producing cells in our bodies are activated by ultraviolet light from the sun and can have a protective effect.• In certain rare circumstances, these vaccines could activate disease.• To be completely safe, he activated his automatic call-signal which would be picked up on the ground.• The different ways in which superantigens activate T cells casts light on the pathogenesis of infectious disease.• The stun gun was applied to parts of her naked body and activated, the jury was told.• The smoke activated the sprinkler system.• Then, their ears protected against the piercing whine, they activated the suction pump.• Room keys activate the temperature controls and turn on an entry light, so guests never enter a dark room.• Baking powder contains its own built-in acid, so it can be activated with just heat and liquid. 