EN 144000 : 1993

Cooperating organizations
National foreword
Foreword
Preface
Section one. Scope
1. Scope
Section two. General
2.1 Related documents
2.2 Units, symbols and terminology
2.3 Preferred values
2.4 Marking
Section three. Quality assessment procedures
3.1 Primary stage of manufacture
3.2 Structurally similar parts
3.3 Qualification approval procedures
3.4 Quality conformance inspection
3.5 Certified test records
3.6 Delayed delivery
3.7 Alternative test methods
3.8 Release for delivery before the completion of
      group B tests
3.9 Formation of inspection lots
Section four. Test and measurement procedures
4.1 Standard conditions for testing
4.2 Drying and recovery
4.3 Visual examination and check of dimensions
4.4 Zero-power resistance
4.5 Temperature coefficient of resistance
4.6 Insulation resistance
4.7 Voltage proof
4.8 Resistance/temperature characteristics
4.9 Dissipation factor at Umax (delta)
4.10 Response time by ambient change (ta)
4.11 Response time by power change (tp)
4.12 Thermal time constant by ambient change (tau a)
4.13 Thermal time constant by cooling (tau c)
4.14 Robustness of terminations
4.15 Soldering
4.16 Rapid change of temperature
4.17 Vibration
4.18 Bump
4.19 Shock
4.20 Climatic sequence
4.21 Damp heat, steady state
4.22 Endurance
4.23 Tripping current
4.24 Non-tripping current
4.25 Residual current
4.26 Surface temperature
4.27 Inrush current
Section five. Blank detail specification
Annex A. Fixed sample size test schedules for
qualification approval
A1. Thermistors for current limitation
A2. Thermistors for heating elements
Annex B. Mountings for electrical measurements
B1. Thermistors without wire terminations
B.2 Thermistors with wire terminations
Annex C. Mountings for temperature measurements
C1. Cylindrical heating elements
C1. Section view
National annex NA (informative) Committees responsible
National annex NB (informative) Cross-references

Describes terms and methods of test for directly heated positive step function temperature coefficient thermistors (PTC-S), insulated and non insulated types, typically made from ferro electric semiconductor materials. Coverage includes related documents, marking, formation of inspection lots, qualification approval procedure, preferred values, and drying and recovery. Also gives detailed annexes.