Analysis of ferroelectric characteristics and HV pulse experiments on X7R ceramic capacitors

X7R ceramic material is regarded as a sound developing direction to produce high energy density capacitors owing to its high dielectric constant (from 3000 to 10/sup 5/) and moderate temperature characteristics. The most important characteristics of X7R is ferroelectricity. In this paper, some samples of HV X7R multilayer ceramic capacitors (MLC) with large capacitance have been made and their electrical behavior in a pulsed discharge circuit have been tested. On the basis of a thorough interpretation of the ferroelectricity, the paper analyzes the special electrical characteristics of MLC, which includes the change of capacitance, particular discharge wave, high dielectric loss, and the life curve. The results of a series of experiments of samples coincided with the above theoretical analysis. In conclusion, the MLC of X7R has good discharge wave, and stable life curve. Some measures must be taken to cool the capacitors due to their high dielectric loss.