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Temperature Measurement · Glossary

What is an NTC Thermistor?

negative temperature coefficientTemperature Measurement

An NTC thermistor is a ceramic semiconductor resistor whose resistance falls strongly as temperature rises.

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NTC Thermistor Explained

Thermistors are very sensitive and cheap, and are used in equipment, HVAC and electronics, usually from about −50 to 150 °C.

Their curve is highly non linear and described with a beta value or the Steinhart Hart equation.

NTC Thermistor Formula

1 ÷ T = 1 ÷ T₀ + (1 ÷ β) × ln(R ÷ R₀)
T, T₀temperatures in K
R₀resistance at T₀, often 10 kΩ at 25 °C
βbeta constant (K)
Example: 10 kΩ at 25 °C, β = 3950 K, R = 5 kΩ: T ≈ 314.6 K, about 41.5 °C.
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Calculators for NTC Thermistor

CalculatorNTC Thermistor CalculatorFree online calculator with formula and worked example.

Frequently Asked Questions

What is an NTC Thermistor?

An NTC thermistor is a ceramic semiconductor resistor whose resistance falls strongly as temperature rises.

NTC or PTC?

NTC resistance falls with temperature and is used for measurement; PTC rises sharply and is often used for protection.

What is the Steinhart Hart equation?

A three coefficient fit, 1/T = A + B ln R + C (ln R)³, more accurate than the beta equation over a wide range.

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