Reversible thermal fusing model of carbon black current-limiting thermistors
Composites of carbon black particles in polyethylene exhibit an unusually rapid increase in resistivity as the applied electric field is increased, making this material commercially useful as current-limiting thermistors, also known as automatically resettable fuses. In this application the composite is in series with the circuit it is protecting: at low applied voltages the circuit is the load, but at high applied voltages the composite becomes the load, limiting the current to the circuit. We present a simple model of this behavior in terms of a network of nonlinear resistors. Each resistor has a resistance that depends explicitly and reversibly on its instantaneous power dissipation. This model predicts that in the soft fusing, or current-limiting, regime, where the current through the composite decreases with increasing voltage, a platelike dissipation instability develops normal to the applied field, in agreement with experimental observations, which is solely due to fluctuations in the microstructure.
- Sponsoring Organization:
- (US)
- OSTI ID:
- 40205610
- Journal Information:
- Physical Review B, Vol. 62, Issue 14; Other Information: DOI: 10.1103/PhysRevB.62.9390; Othernumber: PRBMDO000062000014009390000001; 003038PRB; PBD: 1 Oct 2000; ISSN 0163-1829
- Publisher:
- The American Physical Society
- Country of Publication:
- United States
- Language:
- English
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