Overview
IEC 62319-1:2005 is the international generic specification for polymeric directly heated positive step‑function temperature coefficient (PTC) thermistors. The standard prescribes standard terms, units and symbols, inspection procedures and methods of test for insulated and non‑insulated polymeric PTC thermistors, typically intended for current limiting and overcurrent protection applications. This edition includes the March 2009 corrigendum.
Key topics and technical requirements
The standard defines terminology and the measurement basis used for PTC thermistors and sets out quality assessment and test procedures including:
- Units, symbols and definitions (zero power resistance, nominal resistance, trip event, upper/lower category temperature, etc.)
- Marking and preferred values required in detail specifications
- Quality assessment procedures covering:
- Primary manufacture and subcontracting controls
- Qualification approval and fixed sample‑size test schedules
- Lot release, periodic testing, rework/repair and certified test records
- Test and measurement procedures such as:
- Standard test conditions and drying/recovery
- Visual and dimensional inspection
- Zero power resistance and resistance/temperature characteristics
- Insulation resistance and dielectric (voltage proof) tests for insulated types
- Robustness of terminations, soldering and mounting tests
- Environmental tests: temperature change, climatic sequence, vibration, shock, bump
- Electrical endurance tests: cycle life, trip endurance, trip/hold current, residual current, time‑to‑trip and thermal runaway
- Annexes with normative schedules and mechanical/environmental test definitions (vibration, bump, shock, shear, substrate bending)
Applications and practical value
IEC 62319-1 is focused on the reliable specification and assessment of polymeric PTC thermistors used where devices must limit or interrupt current during fault or surge conditions. Practical uses include:
- Design and qualification of components for circuit protection and inrush/current‑limiting functions
- Creating supplier detail specifications and procurement requirements
- Defining factory test routines, lot release criteria and qualification testing for components in power supplies, consumer electronics and industrial equipment
Who should use this standard
- Component manufacturers and R&D teams specifying polymeric PTC thermistors
- Test laboratories and quality engineers implementing inspection and qualification programs
- OEM design and procurement engineers writing detail specifications for overcurrent protection components
- Certification bodies and IECQ participants assessing compliance and quality systems
Related standards (normative references)
IEC 62319-1 references and aligns terminology and test practices with other IEC/ISO documents, notably:
Keywords: IEC 62319-1, polymeric thermistors, PTC thermistors, current limiting, overcurrent protection, qualification approval, quality assessment, test methods.