A simple example of a Butterworth filter is the third-order low-pass design shown in the figure on the right, with "C" = 4/3 F, "R" = 1 Ω, "L" = 3/2 H, and "L" = 1/2 H. Taking the impedance of the capacitors "C" to be 1/"(Cs)" and the impedance of the inductors "L" to be "Ls", where is the complex frequency, the circuit equations yield the transfer function for this device: