A functional relationship between dielectric constant and voltage for a ferroelectric in the paraelectric state is derived, and Fourier capacitance coefficients for different applied voltage functions are computed. It is shown that because the loss tangent of a ferroelectric in the paraelectric state is proportional to frequency, it can be represented in the same way as a varactor; i.e., as a series resistance and capacitance. It is concluded that since the power‐handling capability of single‐crystalline ferroelectric is virtually unlimited, and since in many cases it has lower loss than a varactor diode, it will soon find wide application in parametric device design.