TMP36: Sensor Voltage to Temperature

Why it’s here

Relate a TMP36 voltage to degrees Celsius.

How it works

The TMP36 relationship used here is temperature = (voltage − 0.5) × 100. At 25 °C the ideal voltage is 0.75 V. Real measurements also depend on reference voltage, noise and sensor accuracy.

Try it

1. Open this experiment
2. Set 0 °C, 25 °C and 50 °C. Run and compare the sensor voltage at each temperature, noting the offset at zero.

Connections

• A0 — TMP36 output
• 5V / GND — Sensor supply

Example sketch

void setup() {
  Serial.begin(9600);
}

void loop() {
  float volts = analogRead(A0) * (5.0 / 1023.0);
  float celsius = (volts - 0.5) * 100.0;
  Serial.println(celsius);
  delay(200);
}

Check your understanding

Why is 25 °C represented by 0.75 V rather than 0.25 V?