The PTC955, manufactured by EPCOS (TDK), is a positive temperature coefficient (PTC) thermistor primarily used for overcurrent protection and self-regulating heating applications. PTC thermistors are ceramic semiconductor resistors that exhibit a large, abrupt increase in resistance when their temperature exceeds a certain level, providing a self-limiting effect.

Applications

• Overcurrent Protection in Power Supplies: Protects power supplies from overload and short-circuit conditions.
• Motor Starting Circuits: Used as a solid-state replacement for starting capacitors in fractional horsepower motors.
• Self-Regulating Heaters: Maintains a constant temperature in applications such as automotive cabin heaters, glue guns, and dehumidifiers.
• Overload Protection for Loudspeakers: Protects loudspeaker drivers from excessive power dissipation.
• Lighting Ballasts: Used for preheating filaments in fluorescent lamps.

Features

• Positive Temperature Coefficient (PTC): Resistance increases sharply with temperature, providing a self-limiting effect.
• Self-Resetting: Automatically returns to its low-resistance state once the overcurrent or overtemperature condition is removed.
• Solid-State Construction: Offers high reliability and long lifespan compared to traditional fuses or thermostats.
• Compact Size: Allows for easy integration into space-constrained electronic circuits.
• High Inrush Current Capability: Can withstand high inrush currents during startup without tripping.

Benefits

• Enhanced Circuit Protection: Provides reliable overcurrent and overtemperature protection, preventing damage to sensitive components.
• Reduced Downtime: Self-resetting capability eliminates the need for manual reset or replacement after a fault.
• Improved Reliability: Solid-state construction ensures long-term reliability and consistent performance.
• Simplified Circuit Design: Easy to integrate into existing circuits due to its simple two-terminal configuration.
• Energy Efficiency: Self-regulating heating capability allows for efficient temperature control in heating applications.

The EPCOS (TDK) PTC955 is a versatile component offering robust overcurrent protection and self-regulating heating capabilities. Its self-resetting nature and solid-state construction make it suitable for a wide variety of applications. Always refer to the official datasheet for specific electrical characteristics, such as switching temperature, resistance values, and voltage ratings, to ensure proper application and performance. Its application depends on its specific electrical characteristics as provided by EPCOS (TDK) documentation.