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Article: Heating with PTC thermistors. (positive temperature coefficient)
- Article from:
- EDN
- Article date:
- June 12, 1996
- Author:
CopyrightCOPYRIGHT 1996 Reed Business Information, Inc. (US). This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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PTC thermistors are indispensable in heating applications where constant temperatures must be maintained. They do not require any extra controls, do not glow at high temperature, and are insensitive to fluctuations in operating voltage.
Thermistors are passive components whose resistance varies with temperature. Positive temperature coefficient (PTC) thermistors are distinguished by a very steep, nonlinear rise in resistance within a small temperature range. The resistance of a typical PTC thermistor, as shown in Figure 1, rises at a rate of 25 percent per kelvin from 240 [degrees] C upwards.
Used as a heating element, the PTC thermistor is heated by an ...