Application of PTC Thermistor
PTC (Positive Temperature Coefficient) thermistors are devices that vary their resistance as a function of temperature in a non-linear manner. They are used for temperature sensing circuits. Its main characteristic is that I cannot exceed the Curie temperature, since doing so it would behave like a NTC.
|Round Ceramic PTC Heating Element||PTC current limiting device||Fuse for PTC overcurrent protection|
A PTC (Positive Temperature Coefficient) thermistor is a variable resistor whose value increases as the temperature increases.
PTC thermistors are used in a wide variety of applications: current limiting, temperature sensing, demagnetization, and for protection against overheating of equipment such as electric motors. They are also used in level gauges, to cause delays in circuits, as thermostats, and as compensating resistors.
The PTC thermistor loses its properties and can eventually behave in a similar way to the NTC thermistor if the temperature becomes too high.
|PTC ceramic heating element||PTC Thermistor for Telecom High Voltage Current Surge Protection||KTY84 Silicon Thermistor|
The differences with the NTC
The temperature coefficient of a PTC thermistor is unique within certain temperature ranges. Outside these ranges, the temperature coefficient is zero or negative.
The absolute value of the temperature coefficient of PTC thermistors is much higher than that of NTC thermistors.
The applications of a PTC thermistor are restricted to a certain temperature range.
1. Dependence of resistance with temperature ·
Change of medium (liquid-air) · Liquid level measurement.
2. Thermal inertia of the PTC · Delay in the activation of relays · Protection against over-current impulses.
3. Positive temperature coefficient · Compensation for negative temperature coefficients PTC thermistors are used in a wide variety of applications, including current limiting, as a temperature sensor, for demagnetization and for protection against overheating of equipment such as electric motors. They are also used in level gauges, to cause delay in circuits, thermostats, and as compensation resistors.
PTCs are used as current limiters and as overload protections.