Conductivity is also called electrical conductivity, which is the main parameter used to describe the fluidity of positive charge in a liquid. Generally, it is used to measure the purity of water. The conductivity of water has a certain relationship with the amount of inorganic acid, alkali and salt. When the concentration is low, the conductivity increases with the increase of concentration. Therefore, this index is often used to estimate the total concentration or salt content of ions in water. In the coating industry, electrical conductivity is an important parameter for water paint.