An apparatus specially developed for the measurement of the resistivity of highly insulating liquids

The progressive improvement in the purification techniques of dielectric liquids renders the measurement of their resistivity more and more difficult, sometimes impossible (especially at room temperature) with conventional AC bridges (SCHERING bridge, transformer ratio bridge) they are not sensitive enough to detect losses (tanδ) or conductance G of a cell of capacitance C filled with a liquid of permittivity ε in the common range of frequencies f (10 to 104 Hz) and to obtain ρ from : tan δ = 1/2πfεp = G/2πfC (1).