Rec. ITU-T K.144 (11/2019)  Surge protective component application guide – Self-restoring thermally activated overcurrent protectors
Summary
History
FOREWORD
Table of Contents
1 Scope
2 References
3 Definitions
     3.1 Terms defined elsewhere
     3.2 Terms defined in this Recommendation
4 Abbreviations, acronyms and symbols
     4.1 Abbreviations and acronyms
     4.2 Symbol
5 Conventions
6 Overview PTC thermistor operation
     6.1 PTC thermistor resistance
     6.2 Polymeric and ceramic material resistance change
     6.3 PTC thermistor overcurrent operation
7 Polymeric PTC thermistor
     7.1 Production
     7.2 Operation
     7.3 Characteristics
          7.3.1 General
          7.3.2 Cold resistance
          7.3.3 Hold and trip currents
     7.5 Ratings
          7.5.1 General
8 Ceramic PTC thermistors
     8.1 Construction
     8.2 Operation
          8.2.1 Resistance (untripped), R
          8.2.2 Electrically powered
     8.3 Production
     8.4 Characteristics
          8.4.1 General
          8.4.2 Resistance R
9 Characteristic parameters
     9.1 General
     9.2 Hold current, Ih, and trip current, It
     9.3 Resistance, R
     9.4 Resistance 1 h after tripping, R1 for polymer PTC thermistors
     9.5 Impulse resistance, Rimp for ceramic PTC thermistors
     9.6 Time-to-trip, ttrip
          9.6.1 General
          9.6.2 PPTC thermistor
          9.6.3 CPTC thermistor
10 Ratings
     10.1 General
     10.2 Impulse voltage withstand
     10.3 AC power fault: maximum current, Imax, and voltage, Vmax
     10.4 Impulse endurance test (life test)
     10.5 AC endurance test (PTC thermistor) (life test)
11 Applications
     11.1 General
     11.2 Telecom POTS protection
     11.3 Power supply overcurrent protection
     11.4 Battery packs
     11.5 Loudspeaker
     11.5 Motors
     11.6 Heaters
Bibliography