The LM35 Precision Centigrade Temperature Sensor is the most trusted analog sensor for projects requiring a linear relationship between voltage and temperature. At Electrapac, we recommend the LM35 because it is incredibly easy to use—it doesn’t require any complex code or libraries, and its output can be read directly by any multimeter or microcontroller with an Analog-to-Digital Converter (ADC).

Product Overview

The LM35 is an integrated-circuit temperature sensor whose output voltage is linearly proportional to the Celsius (Centigrade) temperature. Unlike thermistors which have a curved (non-linear) response, the LM35 provides a predictable 10mV per degree Celsius increase. This means if the sensor outputs 250mV, the temperature is exactly 25°C.

Key Features for Electrapac Customers

• No Calibration Required: The LM35 is internally calibrated during manufacturing, so you don't need to manually adjust your readings or use complex math formulas in your code.

• Low Self-Heating: Because the sensor draws very little current (less than 60µA), it generates almost no heat of its own, ensuring that your readings are a true reflection of the environment.

• Wide Operating Range: Capable of measuring temperatures from freezing cold to boiling hot, making it suitable for both refrigeration and heating projects.

• Linear Output: The simple formula for conversion is:

  

• Robust Interface: Can be used with long wires (up to several meters) with minimal signal loss if paired with a simple bypass capacitor.

Wiring & Integration Guide

The LM35 features three pins. Looking at the flat side of the sensor with the pins pointing down:

1. Pin 1 (Left): V_cc (Power, 4V–30V)

2. Pin 2 (Middle): V_out (Analog Output signal)

3. Pin 3 (Right): GND (Ground)

Pro-Tip: If you are using the LM35 with an Arduino, use the analogReference(INTERNAL) command for higher precision. This changes the ADC reference to 1.1V, providing much better resolution for temperature readings in the typical 0°C to 100°C range.

Primary Applications

• Digital Thermometers: Creating a portable temperature display using an I2C LCD.

• Battery Protection: Monitoring the temperature of Li-ion battery packs during charging.

• HVAC Systems: Simple room temperature monitoring for fans or air conditioning triggers.

• Industrial Cooling: Tracking the heat levels of power transistors and motor drivers.

• Overheat Alarms: Triggering a buzzer or an emergency shutdown if a machine exceeds a safe temperature.

Why Shop at Electrapac?

We supply the Genuine LM35 Series in the convenient TO-92 package, ensuring you get the high accuracy and low-noise performance required for professional builds. Visit us at www.electrapac.com for the precision sensors that bring accuracy to your hardware designs.