DIN EN 60539-1:2017-01

This part of IEC 60539 is applicable to directly heated negative temperature coefficient thermistors, typically made from transition metal oxide materials with semiconducting properties. It establishes standard terms, inspection procedures and methods of test for use in sectional and detail specifications of electronic components for quality assessment or any other purpose. A thermistor is a thermally sensitive semiconductor resistor with the basic function that with the change of the temperature of the component body a significant change of its electrical resistance value is obtained. A temperature-dependent resistor with a negative temperature coefficient (NTC resistor) is a thermistor whose resistance value decreases with increasing temperature. In general, the term "NTC resistor" is used. A directly heated thermistor with negative temperature coefficient is a thermistor whose resistance change is caused by a change in physical conditions. Physical conditions include the current flowing through the thermistor, ambient temperature, humidity, wind velocity, gas and so on. An indirectly heated negative temperature coefficient thermistor is a thermistor whose change in resistance is caused mainly by a change in temperature of the thermistor resulting from a change in current through a separate heater that is in close contact with, but electrically isolated from, the thermistor. The temperature of the hot conductor can also be changed by changes in physical conditions, for example, a current through the hot conductor itself, ambient temperature, humidity, wind velocity, gas, and so on. A temperature-dependent resistor with a positive temperature coefficient is a thermistor whose resistance value increases with rising temperature. In general, the term "PTC resistor" is used. Normative Annex A contains the interpretation of the sampling plans and procedures according to IEC 60410:1973 for use in quality assessment systems, normative Annex B contains the rules for the preparation of detail specifications for directly heated thermistors for electronic equipment for use in quality assessment systems. Informative Annex C describes typical examples of fixtures for the measurement of directly heated thermistors, and informative Annex D contains the reference list to IEC 60539-1:2008. Normative Annex Q describes the quality assessment procedures. When this part of IEC 60539 and related standards are used for the purpose of a complete quality assessment system, the requirements shall be met in accordance with the qualification approval and quality conformity assessment procedures. The responsible committee is DKE/K 614 "Temperatur- und spannungsabhängige Widerstände" ("Temperature- and voltage-dependent resistors") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.