NTC vs. PTC Thermistors: Key Differences Explained

This page clarifies the difference between NTC and PTC thermistors.

Introduction to Thermistors

• A thermistor is a semiconductor device whose resistance changes with temperature.
• It’s also known as a thermal resistor.
• Thermistors come in various shapes and sizes, like rods, discs, and beads.

NTC Thermistor

• NTC stands for Negative Temperature Coefficient.
• In an NTC thermistor, resistance decreases as temperature increases, as illustrated below.
• NTC thermistors are made from oxides of nickel, cobalt, copper, manganese, and other materials.
• They’re commonly used for temperature control and measurement.
• NTC thermistors are typically used in the temperature range of -55°C to 200°C.
• Example: SMD KT series NTC thermistor chips manufactured by ATC Semitec Limited.

PTC Thermistor

• PTC stands for Positive Temperature Coefficient.
• In a PTC thermistor, resistance increases as temperature increases, as illustrated below.
• PTC thermistors are made using barium titanate.
• They are often used to protect electronic circuits from overheating.
• PTC thermistors are generally used in the temperature range of 0°C to 200°C.
• Example: SMD PTC thermistors (TPM series) manufactured by ATC Semitec Limited, which are used as thermal switches.