Thermistors (Temperature Sensors)Glossary

NTC Thermistor is also called 'Negative Characteristic Thermistor' because it has a negative temperature coefficient where the resistance decreases when the temperature is increased.

Temperature compensation is a method to suppress a variation of output characteristic of a component in an electronic circuit by a temperature change.

The constant which shows the change in the resistance calculated by the following formula using the resistance at 2 points at a specified ambient temperature.

B=ln (R/R0) / (1/T-1/T0)
R: Resistance when ambient temperature is T(K), R0: resistance when the ambient temperature is T0 (K)

Maximum voltage is a voltage that can be applied directly to a thermistor. Each data is attached to the detail page for each parts number.

Maximum operating current / voltage is a current / voltage at which the element generates self-heat by 0.1 degree C when applied. If used beyond this value, self-heating will increase and detection error will increase.

It represents the power required to raise temperature of the element by 1 degree C by the self-heating of thermistor in the thermal equilibrium.
Murata defines this as the element alone (not mounted on the board).

The time required for a thermistor held at temperature T0 to reach 63.2% of its temperature difference when it is suddenly changed to ambient temperature T1.

All substances are composed of atoms and molecules, and these atoms and molecules are in constant motion. The movement changes with temperature, and they become more intense as the temperature rises. As the temperature is lowered, theoretically, the movement of atoms and molecules can be completely stopped. That temperature is called absolute zero. There is no temperature lower than this temperature, minus 273.15 degrees Celsius.

Ex）25°C → Absolute temperature 298.15K

PTC Thermistor is also called the positive characteristic Thermistor because it has the characteristic which increases the resistance when the temperature is increased.

The resistance of PTC thermistor remains almost constant up to a certain temperature, and the resistance suddenly increases after a certain temperature. The changing point of this resistance is called the "Curie point (Curie temperature) ", and Murata defines this point as the temperature where the resistance becomes double of the resistance at 25 degree C.

This is a large current which flows beyond a steady state current which occurs when the power supply of electronic equipment is turned on.

Refers to the maximum voltage which can be applied constantly to PTC thermistor within an operating temperature range.

Refers to the voltage which PTC thermistor can withstand when a voltage is applied for 3 minutes in still air at 25°C. A method to apply a voltage gradually from 0V to the withstand voltage is used.

The operating point where the self-heating of PTC thermistor and the heat dissipation to outside became equilibrium states.

In the current-voltage characteristics of POSISTOR, it refers to the current value that can flow without resistance rising (operation).

In the current-voltage characteristics of POSISTOR, it refers to the current value at which resistance rises (operates). Any further current is suppressed.

The hold current or trip current of POSISTOR varies depending on the ambient temperature, resistance value, temperature characteristics and shape.
The current range where a current can flow without operation of POSISTOR is called Hold current range, and the current range that always operate is called Trip current range.
Each current range between the upper and lower limits is called Protective threshold current range. Protective threshold current range includes the product variations.

The operating time refers to the period until the inrush current flowing into PTC thermistor is decreased by 1/2.