PTC Thermistor: Inrush Current Limiter

What is a PTC Thermistor?

A PTC thermistor, or Positive Temperature Coefficient thermistor, is a type of temperature-sensitive resistor used in electronic applications. Unlike other thermistors, it has a positive temperature coefficient, meaning its resistance increases as the temperature rises. This property makes it valuable for tasks like temperature sensing, overcurrent protection, and self-resetting fuses.

PTC thermistors are made from ceramic or polymer materials and are available in various sizes and temperature ranges to suit different applications. They provide a self-regulating solution for controlling temperature and limiting current flow in circuits.

• Temperature Sensing: PTC thermistors serve as sensors that measure temperature in various devices and systems. They increase their resistance with temperature, enabling precise temperature monitoring and control.
• Overcurrent Protection: PTC thermistors act as self-resetting fuses in circuits. When the current exceeds a certain threshold, the thermistor’s resistance rises rapidly, limiting the current flow and protecting the circuit from damage. Once the fault clears, the thermistor resets itself, restoring normal operation.
• Temperature Compensation: PTC thermistors find application in circuits requiring temperature compensation. They help stabilize the performance of components by counteracting the effects of temperature changes, ensuring consistent and reliable operation.

• Motor Starters: Used in motor starters to provide inrush current protection. They limit the initial high current drawn by the motor during startup, preventing damage to the motor windings and associated components.
• Liquid Level Sensing: PTC thermistors can serve for liquid level sensing in various applications. They alter their resistance when exposed to different liquid levels, enabling accurate detection and control of liquid levels.
• Heating Elements: PTC thermistors can act as heating elements in devices such as hair dryers, heaters, and soldering irons. They exhibit a high resistance at low temperatures, generating heat as current flows through them.