CALCULATORS / SENSORS AND INSTRUMENTATION

Thermistor divider and temperature calculator

Beta-model NTC resistance at absolute temperature; beta supplied.

sensors-thermistor.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

This source describes an analytical model. Its quantities and checks are the view.

Scenario	resistanceohm
	3588.18
	2870.55

All calculated quantities are listed with the inputs. Switch to Source to inspect the equations.

SCENARIOS / CALCULATED VALUESSAME SOURCE

Change an input to see the consequences.

resistance range example3588.18 ohm✓ passes

BASELINE INPUTS

referenceResistance10000 ohmreferenceTemperature298.15 Ktemperature323.15 Kbeta3950 K

CALCULATED

resistance3588.2 ohm

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Thermistor divider and temperature
# Scope: Beta-model NTC resistance at absolute temperature; beta supplied.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

referenceResistance = 10000 ohm
referenceTemperature = 298.15 K
temperature = 323.15 K
beta = 3950 K

resistance := referenceResistance*exp(beta*(1/temperature-1/referenceTemperature)) [ohm]

check resistance range example: resistance >= 1000 ohm

scenario alternative: referenceResistance = 8000 ohm

Calculated from your source · not saved

Baseline · Baseline

resistance range example3588.18 ohm ✓ passes

alternative · alternative

resistance range example2870.55 ohm ✓ passes

Illustrative first-order example. Checks are editable requirements, not design standards. The broader topic may require additional equations, data, and validation.

Formula and units

This example uses the following equations. Input names and units match the editable source above.

resistance: resistance = referenceResistance*exp(beta*(1/temperature-1/referenceTemperature)) [ohm]

Original worked example

These are the baseline values in the downloadable source. Edits above let you test your own values.

Given

reference resistance: 10000 ohm
reference temperature: 298.15 K
temperature: 323.15 K
beta: 3950 K

Calculated

resistance: 3588.18 ohm

Assumptions and limits

Beta-model NTC resistance at absolute temperature; beta supplied.

The requirement checks use the limits written in this example. Passing a check does not establish that the model covers every load, material behavior, or operating condition in a real design.

Download this .napkin example ↓

Take it further with your agent

Napkin keeps the inputs, equations, checks and assumptions together in one study. Your agent sets it up; you change the numbers.

Try with Claude ↗

codex 'Use Napkin (https://napkin.engineering/mcp, or the local Napkin plugin) to build a study: Thermistor divider and temperature. Inputs: resistance; beta or Steinhart-Hart data; excitation. Outputs: temperature; voltage; self-heating estimate. Model scope: Measurement chains with explicit noise, bandwidth and calibration. Read napkin_capabilities and the current snapshot. Ask me for the values that matter, label assumptions with units, author .napkin source, validate it and apply it with napkin_source using the current revision, then open the study. Add checks for the limits I supply. Keep unsupported analyses explicit.'

Claude needs the Napkin connector; Codex needs the Napkin plugin. Set up your agent ↗

The broader study

The topic brief below describes the broader scope. The worked example above states the particular calculation it implements.

Inputs: resistance, beta or Steinhart-Hart data, excitation
Outputs: temperature, voltage, self-heating estimate
Modes: calculate, compare, sweep
Drawing: Signal-chain and error plots

EXECUTABLE WORKED EXAMPLE · FIRST-ORDER MODEL · CHECK THE SCOPE & ASSUMPTIONS