In which Olympics were electric timing devices used for the first time?

The 1912 Summer Olympics (Swedish: Olympiska sommarspelen 1912), officially known as the Games of the V Olympiad, were an international multi-sport event held in Stockholm, Sweden, between 5 May and 22 July 1912. Twenty-eight nations and 2,408 competitors, including 48 women, competed in 102 events in 14 sports.

The games were the first to have art competitions, women's diving, women's swimming, and the first to feature both the decathlon and the new pentathlon, both won by Jim Thorpe. Electric timing was introduced in athletics for the first time.

The athletic events saw the introduction of an fully automatic timing system developed by R. Carlstedt. It involved attaching electromagnets to chronometers in a system which attached a control lamp to the starting gun for each race. This resulted in the firing of the gun starting a timer which was then stopped by one of the judges at the finishing line.

The final of the men's 100 metres was expected to be a mostly American affair. It ended up with six athletes, only one of whom was not from the United States. It suffered from seven false starts before the athletes finally got away, with Ralph Craig winning the gold medal by 60 centimetres (24 in) in front of second place Alvah Meyer.