Vacuum Glossary

  • Bayard Alpert

    The hot cathode sensor of Bayard Alpert type ionizes gas molecules by electron bombardment. The resulting ion current is a measure for the number of gas molecules present in the sensor and proportional to the absolute pressure.
  • Capacitance [Measuring principles ]

    Under the influence of pressure a thin diaphragm is bent, on the back of which an electrode is applied as part of a capacitor. The bending of the diaphragm thus results in a change in capacity, which is a measure for the applied pressure.
  • Cold Cathode [Messprinzipien ]

    The cold cathode sensor of type inverted magnetron creates ionized gas molecules by an electric discharge. The resulting ion current is a measure for the number of gas molecules present in the sensor and proportional to the absolute pressure.
  • Impulse Pirani [Messprinzipien ]

    The impulse Pirani uses the heat conduction of gases for measuring vacuum. A sensor filament is heated to a certain temperature threshold in pulsed mode, the time needed for heating is a measure for total gas pressure.
  • Piezo [Measuring principles ]

    Under the influence of pressure a thin diaphragm is bent, on it's back a resistor-bridge is applied. The bending forces the measurement-bridge to come out of tune, which is a measure for the applied pressure.
  • Pirani [Messprinzipien ]

    The Pirani principle uses the heat conduction of gases for measuring vacuum. A sensor filament in a Wheatstone circuit is heated to a constant temperature, so the bridge voltage is a measure for total gas pressure.
  • Vacuum Transducer

    Also vacuum gauge or vacuum transmitter, converts an absolute pressure measured by a sensor element into an analog (4-20 mA, 0-10 V) or digital output signal.