• Ionization vacuum gauges work by charged molecules (ions) being attracted and counted as they pick up an electron to become neutral again.

• Ionization gauges have a hot filament, grid and ion collector. A control unit provides power, amplification and metering. The hot filament supplies ionizing electrons and the grid attracts them. The ion collector also attracts the ions and gives up electrons as ions are neutralized creating a small ion current which is amplified.

• Electrons collide with gas molecules, ionizing them and releasing more electrons. The longer the grid flight of electrons the greater number of collisions are possible. Therefore, a stronger, mover usable signal is produced.

• Nude gauges are mounted directly in the chamber.