Vacuum relays are widely used in airborne, mobile and marine communications equipment. Typical applications include antenna coupling, tap changing on radio frequency (RF) coils, transmit and receive switching to an antenna, switching in pulse-forming networks and heavy duty power supplies.
Vacuum is the ideal dielectric for high voltage relay switching. It has extremely high voltage breakdown characteristics, a fast recovery rate (up to 10 kV per millisecond) and it provides an absolutely inert and non-reactive environment for switching contacts. Since there is no oxygen in a vacuum, contacts remain oxidation free.

Here are two common relay types:
Clapper type relay

Diaphragm relay

Typical Applications

RF Applications
Vacuum relays play a vital role when high power and low RF losses are required.
• Vapor deposition for semiconductor wafer processing
• Transmitter/receiver switches
• Pulse forming networks
• Ion implant
• MRI power supplies
• Radar systems
• Security screening systems
• TWT power supplies
• Radio antenna tuning matching circuits

Test equipment and instrumentation
• ESD pulse forming equipment
• HiPot testing
• Cable testing
• Motor winding testing
• Mega-ohm testing
• High power lasers
• Power supply testing
• Mass spectrometry
• High voltage power supplies
• Transformer test equipment
• Ballast test equipment