Electromagnetic pulse

An electromagnetic pulse (also known as EMP) was a discharge of electromagnetic radiation that could render the technology of certain races temporarily inert.

Uses
In Pete's World, the Preachers possessed EMP bombs created by Mrs. Moore that were used to destroy computers. Using one on a Cyberman had the effect of crippling it and disabling it's Emotional inhibitor. (DW: The Age of Steel) An EMP device was used when the Preachers attacked the Cybus factory in Paris. (VG: Save Paris)

Since Bannakaffalatta was a Cyborg, his body contained an EMP device, which was capable of shutting down Heavenly Hosts. However, they were only stunned temporarily. In using the EMP pulse, Bannakaffalatta drained almost all his power, dying shortly after. However, Bayldon Copper, Astrid Peth and Rickston Slade were able to obtain the EMP device, recharged it, and used it as a weapon against the other Hosts. (DW: Voyage of the Damned)