Sensor Interface Calculators
17 free calculators with formulas and worked examples.
NTC thermistor, RTD, thermocouple, Wheatstone bridge, load cell, 4-20 mA transmitter, photodiode transimpedance, and sensor accuracy budget calculators.
NTC Thermistor
Calculate temperature from NTC thermistor resistance using the Steinhart-Hart beta equation. Get Kelvin and Celsius outputs for sensor circuit design.
RTD Temperature
Calculate temperature from PT100 or PT1000 resistance — enter measured ohms, get °C instantly. Uses the Callendar-Van Dusen linear approximation. Includes presets for common PT100 values (119.4 Ω = 50 °C, 138.5 Ω = 100 °C).
Wheatstone Bridge
Calculate Wheatstone bridge output voltage, balance condition, and mV/V sensitivity. Design circuits for strain gauges, RTDs, and load cells.
Hall Effect Sensor
Calculate Hall voltage V_H = R_H·I·B/t, carrier density, and sensitivity for Hall effect sensors. Covers magnetic field measurement, current sensing, and position detection applications.
Strain Gauge Bridge
Calculate bridge output voltage for strain gauges in quarter, half, and full bridge configs. Determine mV output and resistance change for load cells.
PT100 Resistance
Calculate PT100 or PT1000 RTD resistance at any temperature using the Callendar-Van Dusen equation. Get resistance and sensitivity per IEC 60751.
Thermocouple
Calculate thermocouple EMF voltage from temperature with cold junction compensation. Determine Seebeck output for Type K, J, T, and E sensors.
Load Cell Amp
Calculate load cell output voltage, required amplifier gain, and mV/V sensitivity for Wheatstone bridge weigh scale and force sensor designs.
TIA Design
Calculate TIA output voltage, bandwidth, and noise for photodiode circuits. Design transimpedance amplifier gain and feedback components.
Capacitive Sensor
Calculate capacitance and sensitivity (pF/mm) between sensor plate and target. Design capacitive proximity and touch sensor detection circuits.
Current Shunt
Calculate shunt resistor voltage drop, power dissipation, amplifier output, and ADC resolution for current sensing circuits. Free, instant results.
Accelerometer
Calculate accelerometer output voltage, ADC resolution in mg per LSB, and full-scale range. Design MEMS vibration and motion sensor interfaces.
Pressure Bridge
Calculate bridge output voltage for piezoresistive pressure sensors. Determine mV output from excitation voltage, sensitivity, and applied pressure.
Sensor Accuracy
Calculate total sensor error using RSS and worst-case methods. Analyze offset, gain, nonlinearity, resolution, and temperature drift contributions.
Optical Range
Compare optical proximity sensor configurations by detection factor. Analyze emitter power, detector responsivity, and reflectivity tradeoffs.
LVDT
Calculate LVDT output voltage, sensitivity in mV/mm, and linear range from excitation voltage and stroke. Design displacement sensor signal chains.
4-20mA Loop
Calculate 4-20 mA current loop voltage budget, sensor value from loop current, and maximum loop resistance for industrial transmitter design.
About Sensor Interface Calculators
Sensor interface electronics converts physical phenomena — temperature, pressure, strain, light, current — into digital values that a microcontroller or data acquisition system can process. Every sensor interface involves a signal chain: transducer, conditioning amplifier, filter, and ADC, each contributing noise, offset, gain error, and nonlinearity to the total measurement uncertainty.
Thermistors (NTC/PTC) and RTDs are resistance-based temperature sensors. NTC thermistors have steep, nonlinear resistance-temperature curves described by the Steinhart-Hart equation; linearization is required over wide temperature ranges. RTDs (PT100/PT1000) have near-linear positive temperature coefficients and higher accuracy but lower sensitivity. Both require excitation current and a Wheatstone bridge or ratiometric circuit to convert resistance to voltage.
Thermocouples generate a small voltage (10-50 μV/°C) from the Seebeck effect at the junction between two dissimilar metals. Accurate measurement requires cold-junction compensation — measuring the reference junction temperature with a separate sensor and adding the corresponding voltage — and precision instrumentation amplifiers with low offset voltage drift.
Load cells and pressure sensors use strain gauges in Wheatstone bridge configurations. Full-scale output is typically 1-3 mV/V of excitation, requiring gain of 500-1000× before ADC conversion. Instrumentation amplifiers (INA128, AD8221) provide high CMRR to reject common-mode noise on long cable runs. The 4-20 mA current loop standard transmits sensor readings over long distances with immunity to ground loops and cable resistance — universal in industrial process control.