LM335 Temperature Sensor

The LM335 is a high-precision temperature sensor integrated circuit (IC) that offers a linear voltage output that varies with temperature. The following information provides a comprehensive overview of the LM335 sensor:

Features of the LM335 Sensor

• Temperature Range:
  • Operating: -40°C to +100°C
  • Calibrated: 0°C to +100°C
  • Full Range: -55°C to +150°C
• 
  Output Voltage: Linearly proportional to temperature at 10 mV/°C
• Calibration: Factory-set to yield an accurate output voltage for a specified temperature range.
• Accuracy: Typically ±1°C at +25°C, and ±2°C over the full -40°C to +100°C range.
• Power Supply: Generally operates between 2.4V and 30V DC.
• Output Configuration: Delivers a linear output voltage that can be directly interfaced with ADCs, microcontrollers, or other measurement devices.
• Low Impedance Output: The output impedance is low, making it ideal for driving long cables without significant signal degradation.
• Low Quiescent Current: Consumes minimal current, making it suitable for battery-powered applications.

Applications of the LM335 Sensor

• Temperature Measurement: Utilized in various applications where accurate temperature monitoring is necessary, such as environmental monitoring systems, industrial control systems, and automotive applications.
• Temperature Compensation: Frequently used in circuits that require temperature compensation, such as in analog circuits and sensor modules.
• Portable Devices: Due to its low power consumption and compact size, it is ideal for integration into handheld and portable devices.

Example Circuit

Here's a basic example of how you might connect an LM335 sensor to an Arduino for temperature measurement:

const int lm335Pin = A0;  // LM335 analog pin connected to Arduino analog input A0void setup() {
  Serial.begin(9600);    // Initialize serial communication
}void loop() {
  int sensorValue = analogRead(lm335Pin);  // Read analog input
  float voltage = sensorValue * (5.0 / 1023.0);  // Convert analog reading to voltage (assuming 5V Arduino)
  
  // Convert voltage to temperature using LM335 formula (10 mV/°C)
  float temperatureC = (voltage - 2.73) / 0.01;  // 2.73V is the LM335 sensor's output at 0°C, 0.01V/°C is the slope
  
  // Print temperature to serial monitor
  Serial.print("Temperature: ");
  Serial.print(temperatureC);
  Serial.println(" °C");
  
  delay(1000);  // Delay before next reading
}

Explanation

Connect the LM335 sensor's Vout pin to Arduino's analog input pin (A0 in this example). In the Arduino sketch, read the analog voltage from the sensor using the analogRead() function. Convert the analog reading to voltage using the formula (sensorValue * (5.0 / 1023.0)), assuming a 5V Arduino. Use the LM335 formula (voltage - 2.73) / 0.01 to convert voltage to temperature in degrees Celsius. Print the temperature readings to the Serial Monitor. This example demonstrates how to interface the LM335 sensor with Arduino for temperature measurement. Adjust the code as needed based on your specific setup and requirements.