transistor package. All the complicated circuitry has built in side the IC by the manufacturer and therefore it doesn't require external components. Only you have to connect a battery or power supply that can be any from 4 to 20 volt DC, a multimeter preferably digital and you are ready to measure the temperature.

Another great quality of this IC that the current consumption is only 60uA, therefore it can work thousand of hours on simple batteries.

The LM35 temperature sensor circuit IC senses the temperature and provides output voltage equals to 10mV per centigrade. A multimeter can easily read this output voltage by selecting 2000mV DC mode. Reading the temperature is very easy for example if your room temperature is 33 centigrade then your digital multimeter will display 330mV and if your room temperature is 33.5 centigrade then your meter will show 335mV.

You can also make a simple resistive divider from which you will get 1mV per centigrade on the multimeter. You can also read this output by selecting 200mV mode option on your multimeter. This will show you more accurate results for example if your room temperature is 33 centigrade then you will get exact 33mV on your multimeter. Making a simple resistive divider is shown in figure 2.

You can also connect the LM35 sensor with long wires, by doing this you can easily measure the temperature of objects, electronic components, circuits and small places where a big thermometer can't be reached.

This IC cannot be only used for temperature readout but it can also perform variety of temperature sensing tasks in electronic circuits. If you want to make a fahernheit temperature sensor then you can use the other version LM34 (Fahrenheit temperature sensor) in the place of LM35. 

Privacy Policy
Copyright 2013 CircuitDiagram.Org. All rights reserved.
Here is an easy & accurate digital thermometer circuit that can be used for variety of purposes like monitoring indoor or outdoor temperature, checking temperature of electronic components and circuits etc.
The circuit is very simple and can be made by using LM35 IC available in TO-92
Sponsored Links
Digital Thermometer Circuit
Figure 1.
In Figure 2 we have shown how to make a simple resistive divider. We have used a 10K ohms resistor and a 2K variable resistor.

After building the circuit connect the battery and select 2000mV option in multimeter. Now connect the negative lead of the multimeter to the ground of the circuit and positive lead of the multimeter directly with the LM35 pin 2 to check what temperature the IC is showing without resistive divider. Now select 200mV option in multimeter and connect the positive lead of the multimeter with the resistive divider as shown in the figure 2 and slightly adjust the 2K variable resistor until you get equal temperature as you seen without the resistive divider.   

Figure 2.