Lothian and Borders Police has become the latest force in Scotland to introduce Taser stun guns.
Two people have been overpowered with Tasers in Scotland
The weapons were made available to officers in the Strathclyde Police area in September 2005.
Officers in Dumfries and Galloway and Northern Constabulary have also been trained in their use, the Assocation of Chief Police Officers in Scotland said.
Human rights campaigners have spoken out against the use of Tasers following the deaths of several people in the US.
Most forces in England and Wales have begun using the weapons, which are intended as a less lethal alternative to firearms.
The weapons discharge an electrical charge and are designed to incapacitate rather than cause serious injury to a person.
Ian Dickinson, Assistant Chief Constable of Lothian and Borders Police, said the guns would be deployed alongside firearms to deter dangerous individuals.
He said experience elsewhere showed that most suspects, when faced with a warning from officers and the red Taser light, immediately surrendered.
"Armed officers often need to deal with people who are threatening officers' lives or the life of an innocent person," said Mr Dickinson.
"When armed officers are faced with such a threat they do not know, and cannot know, exactly how serious and dangerous it is.
"Having a Taser available gives officers the option of dealing with the threat to life without having to resort to use of a firearm which carries a risk of killing the individual."
Two people have been temporarily disabled with Tasers since they were introduced in the Strathclyde force area.
The suspects were overpowered by officers at filling stations in North Lanarkshire and Glasgow in separate incidents last November.