In the equilibrium of forces between the electric force $$F_{\text e}$$, the buoyancy force $$F_{\text a}$$ and the falling force $$F_{\text g}$$, the oil droplet levitates. It thus experiences no frictional force $$F_{\text R}$$. This floating state of the oil droplet is used in the levitation method to find out the elementary charge $$e$$ with the help of given forces.