bomb detonator
A detonator is a small explosive device that activates a larger bomb while ensuring a time delay for safety. Detonators can be electrical, chemical, mechanical, or wireless, meaning that a cellphone can be used to trigger the electrical charge necessary to initiate the larger explosion. In most detonating mechanisms, a fuse that is inserted into the larger explosive device is set off by connected chords that run an electrical charge from the detonator to the bomb itself.