Titanium‐Based Dual‐function Varistor Ceramics

Miniaturizing electronic devices is always a desirable target. The integration of electronic circuitry into integrated circuit (IC) chips has brought large volume and weight reductions, so the application of varistors within low-voltage field also rose. ZnO varistor is difficult to achieve using low-breakdown voltage technology but mainly for the high-voltage varistor. Capacitor–varistor dual-function components, such as TiO2, SrTiO3, and CaCu3Ti4O12 (CCTO) varistors, have realized the goal to achieve component miniaturization and provide superior high-frequency and high-amplitude transient voltage protection. Because of its outstanding dielectric properties and non-ohmic characteristics, and simple and straightforward preparation, CCTO is considered a very promising capacitor–varistor dual-function material. Another kind of titanium-based dual-function ceramics is donor-doped BaTiO3 ceramics, which behaves positive temperature coefficient of resistivity (PTCR) performance and nonlinear V–I property, and have been extensively used in current-limiting applications, such as overload protection devices, delay line switches, and self-regulating heaters.