PTC/NTC Thermistor UL1434 Certification

JJR LAB is a third-party testing agency authorized by UL, operating its own independent testing laboratory. The laboratory possesses UL1434 witness-exempt testing qualifications and can provide UL certification, testing, and technical consulting services for PTC and NTC thermistors.

What is a Thermistor?

A thermistor is a type of sensitive component. Based on their temperature coefficients, they are divided into Positive Temperature Coefficient (PTC) thermistors and Negative Temperature Coefficient (NTC) thermistors.

The typical characteristic of a thermistor is its sensitivity to temperature, exhibiting different resistance values at different temperatures:

• For a Positive Temperature Coefficient (PTC) thermistor, the higher the temperature, the greater the resistance value.

• For a Negative Temperature Coefficient (NTC) thermistor, the higher the temperature, the lower the resistance value.

Both are classified as semiconductor devices.

Classification of Thermistors

• By Material: Semiconductor thermistors, metal thermistors, and alloy thermistors.

• By Temperature Coefficient: Positive Temperature Coefficient (PTC) thermistors and Negative Temperature Coefficient (NTC) thermistors.

Required Information for a ul certification testing Quote

1. For a Preliminary Inquiry:

• Product images

• Functional description

• Product name

• Dimensions and usage instructions

• Explanation of differences between models

• Information on whether materials have obtained certification

2. For an Accurate Quote:

• Product manual

• Explanation of differences between models

• Structural diagrams and circuit schematics

• List of critical components

• BOM (Bill of Materials)

3. For a Testing & Certification (Report Writing) Quote:

• Product manual

• Explanation of differences between models

• Structural diagrams and circuit schematics

• List of critical components

Thermistor UL Certification Standards

UL 1434

1. Applicable to discrete thermistor-type devices made of ceramic or polymeric semiconductor materials.

2. Applicable to self-heating devices (such as heaters), control devices (such as current limiters and inrush current limiters), and sensing devices.

3. Applicable to Positive Temperature Coefficient (PTC) and Negative Temperature Coefficient (NTC) type devices.

4. Applicable to control devices, such as current limiters, which are not intended to replace current-interrupting devices like fuses, but rather to provide overcurrent protection that complies with the requirements of the end-use equipment.

Thermistor UL Certification Testing Items

To improve readability, the original text's symbols have been removed and formatted into a clear list:

• Surface Temperature Verification Test

• Transient Current and Trip Time Verification Test

• R/T (Resistance-Temperature) Curve Verification Test

• Dielectric Voltage-Withstand Test

• Thermal Aging Test

• Heat, Cold, and Humidity Cycling Test

• Overload Test

• Endurance Test

• Cold Operating Cycle Test

• Short-Circuit Test

• Thermal Breakdown Test