# Thermistor R/T Calculators

## Calculators for Temperature & Thermistor Applications

Beta Value Calculator - The approximate relationship between the resistance and temperature for a NTC thermistor.

Defense R – T (Resistance vs. Temperature Tables) – M23648 and M32192 Defense Ratios for defense and aerospace applications use slightly different values than QTI’s standard curves. MIL-PRF and NSAS/GSFC parts always use MIL-spec curves.

R – T (Resistance vs. Temperature Tables) – A table showing the standard resistance at each temperature point.

Steinhart-Hart Calculator - The Steinhart–Hart equation is a model of the resistance of a semiconductor at different temperatures. • T is the temperature (in Kelvin)
• R is the resistance at T (in ohms)
• A, B, and C are the Steinhart-Hart coefficients which vary depending on the type and model of the thermistor and the temperature range of interest. (The most general form of the equation contains a (IN(R))2 term, but this is frequently neglected because it is typically much smaller than the other coefficients, and is therefore not shown above.)

## Calculators for Temperature & Thermistor Applications

To find degree tolerance - Add standard part tolerance to maximum deviation and divide by the NTC value.

To find percent tolerance - Multiply degree tolerance by NTC value.