Proximity fuze

The proximity fuze is a device within an artillery shell that detonates it when it approaches the target. It was first employed by the British and Americans late in World War II. The fuze uses radar and the doppler effect. It was made from miniaturized electronic components that were very advanced for the time, and they were carefully packed with wax and oil to minimize the stress of being launched. Four miniature vacuum tubes were used.

Proximity fuzes were especially useful against aircraft and personnel.

During the Battle of the Bulge, German human-wave style attacks were decimated by Allied artillery using these shells.