A Langmuir probe is used to measure the electron density, electron temperature, and electric potential of a plasma. A four-quadrant bipolar power supply is connected to the electrodes in the plasma, and a sinusoidal or triangular voltage is applied. The Langmuir probe method is a method to determine the plasma state by analyzing the swept voltage and current.

The specifications of the bipolar power supply required for plasma measurements depend on the electron temperature, electron density, and potential of the plasma.
Typically, a four-quadrant power supply with a voltage of ±100V, a current of 1-2A, and a frequency of about 100Hz is used.

Related words