Abstract : 0-100C electronic temperature controlled relay is a circuit using which the temperature can be controlled with the help of a LM35 temperature sensor.

The LM35 series are precision integrated-circuit temperature sensors, whose output voltage is linearly proportional to the Celsius (Centigrade) temperature.

The LM35 thus has an advantage over linear temperature sensors calibrated in˚ Kelvin, as the user is not required to subtract a large constant voltage from its output to obtain convenient Centigrade scaling.

The LM35 does not require any external calibration. Using a precision reference (TL431) a temperature is set and an accurate comparator inorder to construct a simple thermal controlled switch.

The temperature that is set is compared with the output of the LM35 which decides whether to energize or de-energize the relay. An LED and an alarm is used to indicate when the device crosses the set temperature.

The circuit is very useful in practical areas like heater,iron box etc.

Please find the following attachments"Electronic Temperature Controlled Relay seminar report/pdf/ppt download" here.......