Temperature Sensor Front-End Calculator
Design an NTC or PT100/PT1000 front-end (resistor divider or constant current) and see the output voltage vs temperature, sensitivity, and ADC resolution.
Updates live as you change the inputs.
Turning a sensor's resistance into a voltage
A temperature sensor is a resistance that changes with temperature. To read it with an ADC you convert that resistance to a voltage — most often with aresistor divider (a fixed pull-up resistor in series with the sensor) or a constant-current source (which gives a voltage directly proportional to resistance).
Divider: Vout = Vs · R / (R + Rf)
Constant current: Vout = I · R
For a divider, sensitivity (mV per °C) is highest when the fixed resistor roughly equals the sensor's resistance at your target temperature — the suggested value uses that rule. A parallel resistor across an NTC trades some sensitivity for a straighter response, shown on the graph as the "without Rp" comparison.
The ADC resolution figure is the temperature step per code (Vref ÷ 2^bits ÷ sensitivity) at the target — useful for checking whether a given ADC resolves finely enough.
Linearisation works over a range, not everywhere
A parallel linearising resistor straightens a thermistor's curve over a chosen span and makes it worse outside that span. The improvement is real but local, so the range you optimise for matters as much as the resistor value. Beyond that, the same practical limits apply as to the sensor pages themselves: self-heating from the excitation current, lead resistance in a two-wire connection, and the ADC's own resolution and noise floor, which often set the achievable accuracy well before the sensor does.