Temperature & Sensors Calculator
Convert temperature units and calculate resistance-to-temperature mapping for NTC and PT100 sensors.
Unit Converter (all editable)
NTC Thermistor / PT100 RTD
NTC Temp Output—
PT100 Temp Output—
💡 Usage & Formula
Temperature Sensors like NTC Thermistors (nonlinear resistance) and PT100 RTDs (linear resistance) require specialized equations to translate resistance measurements into degrees.
Formulas:
- NTC Beta Equation:
1/T = 1/T25 + (1/B) * ln(R / R25)(T in Kelvin) - PT100 RTD (Linear approximation):
T = (R - 100) / 0.385
Usage: Convert temperature units dynamically, or input thermistor parameters (R25, Beta) and measured resistance to solve for temperature.
When you need it: Converting between °C, °F and K, and translating a thermistor, RTD or thermocouple reading into a temperature in firmware.
Worked example: 100 °C = 212 °F = 373.15 K. An NTC thermistor follows the Beta equation, while a Pt100 RTD reads 100 Ω at 0 °C and rises about +0.385 Ω/°C.
Tips & gotchas:
- NTC thermistors are strongly nonlinear — use the Beta or Steinhart-Hart model, never a straight line, over a wide range.
- RTDs are nearly linear but low-sensitivity, so lead resistance and excitation current matter.
- Thermocouples measure a difference and need cold-junction compensation to give an absolute reading.
- Excitation current self-heats the sensor; keep it small or account for the offset.
📖 References:
Temperature scale conversion (Wikipedia)