Zinc oxide varistor time response
The application of a voltage to a zinc oxide varistor produces transient currents that persist on a time scale extending from 10/sup /minus/8/ to 10/sup 5/ seconds at the least. The transient currents are characterized by a power-law time dependence (i.e., I =I/sub o//t/sup m/, where m is a little less than unity) and a weak temperature dependence that is described by a thermal activation energy of about 100 meV or less. The time dependence is confirmed by an ac admittance that increases as a noninteger power of the frequency (i.e., Y = K(j..omega..)/sup m/), with Fourier theory providing the connection between the time and frequency measurements. Also, the transient currents are accompanied by changes in the ac admittance measured at fixed frequencies that reveal similar time and temperature dependencies. The transient currents are not well understood, but they are typical of the non-Debye electrical response that is found in many materials. An explanation of the transients is obtained if a distribution of relaxation times is assumed. 7 refs., 6 figs.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6475360
- Report Number(s):
- CONF-881275-1; ON: DE89008234
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
420800* -- Engineering-- Electronic Circuits & Devices-- (-1989)
CHALCOGENIDES
CURRENTS
ELECTRIC CURRENTS
ELECTRICAL EQUIPMENT
ELECTRICAL TRANSIENTS
EQUATIONS
EQUIPMENT
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RELAXATION TIME
RESISTORS
TEMPERATURE DEPENDENCE
TRANSIENTS
VOLTAGE DROP
ZINC COMPOUNDS
ZINC OXIDES