The paper reports on the dielectric response and conductivity calculation based on the absorption current and the recovery voltage measurements. The time-domain measuring methods have been used for assessment of an electrical grade ceramics made from quartz and alumina porcelain. The measured data were converted into the form of complex permittivity. Experimental results indicated occurrence of a polarization process with relaxation time of about 100 s. The relaxation time and the conductivity appear to be very sensitive to the temperature variation. They could be prospective indicators of the changes generated by temperature and ageing of material.