The LM35 series temperature sensor is a temperature sensor in the form of an integrated circuit, where the output is a voltage that is linearly proportional to the Celsius temperature (Centigrade). So LM35 has a feature compared to a linear temperature sensor which is usually expressed in Kelvin, ie the user does not need to reduce the sensor output with a constant number of 273 0.
Characteristics of IC LM35:
- LM35 does not require external calibration, with an accuracy of ยฑ ยผ ยฐ C at room temperature, or ยฑ ยพ ยฐ C for the measurement range of -55 to + 150 ยฐ C.
- It has a low output impedance, linear output, easy to operate and combined with the next circuit such as the control circuit.
- LM35 can be operated with a single power supply or dual power supply (plus and minus), and only requires 60 ฮผA of current, the heat produced is not too high (less than 0.1 ยฐ C) even without cooling.
- LM35 is able to measure temperature with a range of -55 ยฐ to + 150 ยฐ C, while for the LM35C series it has a measurement range of -40 ยฐ to + 110 ยฐ C.
The LM35 series packaging is in the same shape as the TO-46 transistor packaging, while the LM35C, LM35CA and LM35D series are also available in TO-92 packaging, and the LM35D series are also available in TO-220 packaging.
LM35 circuit diagram:
The circuit of the temperature sensor has terminals as two inputs, such as not invert (+) and invert (-) and only one output pin. The operational amplifier IC741 is used as a non-inverting amplifier. The variation between the terminals I/p amplifies the circuit.
This unstable voltage is supplied to a comparator IC 741. OP Amplifier is the electronic device most used today. The operational amplifier IC 741 is a type of differential amplifier. We have used IC741 as a non-inverting amplifier, which means that the pin-3 is the input and the output is not inverted. This LM35 temperature sensor circuit amplifies the difference between its input terminals.
