Time constant equal to the time in seconds for charge to decay by Ohm's Law to e-1 (36.7%) of its initial value. For a capacitor, the time constant (s) is the product of resistance (W) and capacitance (F). For a charged material sample, either solid or liquid, the time constant is the product of permittivity (F/m) and resistivity (W-m).
Go to Process Safety Glossary