Lm35 Temperature Sensor Pin out, Interfacing guide, Circuit Construction and Working Principal. Lm35 is a temperature sensor that outputs an analog signal. In principle, the sensor will perform sensing when the temperature changes every 1 ÂșC temperature will show a voltage of 10 mV. In placing the. temperature (measured in Kelvin) into either Fahrenheit or Celsius, depending on the part (LM34 or LM35).

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After following links through Quora and Edaboardit basically princippal down to Wikipedia: The datasheet has a “detailed description”, did you read that? Bandgap voltage reference Silicon bandgap temperature sensor Basically, it boils down to the fact that the voltage across a PN junction the BE junction of a transistor varies both with current density and with temperature.

It is the thermal voltage which is given by this formula: I understand some parts of the internal circuit in the datasheet, but I can’t seem to find how it seems to work. Can someone explain it to me like I’m a total noob when it comes to electronics? Now the fun part is, that the base-emitter voltage of a transistor behaves just the same way as a diode. Is there an underlying physics explanation to it? Email Required, but never shown.

Furthermore, for any queries regarding this article or any help in implementing the electronics projectsyou can feel free to approach us by connecting in the comment section below. At that level a lot is going on and it is hard to keep the balance between how deep to go and sometimes I forget the most important parts. It is also mostly used for non-scientific purposes as it is not so accurate. I see, I can settle with that. OP Amplifier is the most generally used electronic devices today.

Explanation is good and thorough, I get it now.

Working Principle of Temperature Sensor and Its Application

How does the LM35 Temperature sensor work? This is all about temperature sensor circuit and its working principle. To get a feeling for it: This sensor generates a high output voltage than thermocouples and may not need that the output voltage is amplified.

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Also the typical diode has an ideality factor which is not as close to 1 as you would like it to be. Thank you so much for your feedback And once again please visit our woriing website http: Home Questions Tags Users Unanswered. Temperature is one of the most frequently calculated variables and sensing can be made either through straight contact with the heating basis or remotely, without straight contact with the basis using radiated energy in its place.

Certain chemical effects, biological processes, and even electronic circuits execute best in limited temperature ranges. The amount produced by IC2 amplifies in an amount to the temperature by 10 mV per degree. So you can solve the above equation to read: Another workinf you eliminate is the complex temperature dependency of the saturation current, which limits the linearity of your voltage principxl.

Yes, the datasheet merely details how to use it, not how it works fundamentally, as you say. Hi Yes, you can use. Let’s start with a simple diode which is not how it is done in the LM Our professor requires us to have a thorough explanation of how they work. By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

AliChen, seems a pointlessly harsh comment, OP had their answers already and is just trying to learn, as we all do.

LM35 Temperature Sensor Circuit and Its Working

Post Your Answer Discard By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the workint is subject to these policies. By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies. That’s a solid-state physics question that starts to get into the quantum-mechanical properties of the charge carriers.


We have used IC as a non-inverting amplifier which means pin-3 is the input and the output is not inverted. Sign up using Facebook.

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This unstable voltage is supply to a comparator IC Like, how exactly does having different current densities for the emitter cause a voltage for the resistor. So what is the benefit of this compared to the diode above? The scale factor is. The current through a diode is given by the Shockley equation which neglects the series resistance which is fine for our use: It can measure temperature more correctly compare with a thermistor.

Operational amplifier IC is used as a non-inverting amplifier.

The advantages of temperature sensor include It has no effect on the medium, more accurate, It has an easily conditioned output and It responds instantly. The different types of temperature sensors include the following.

How does the LM35 Temperature sensor work? – Electrical Engineering Stack Exchange

After following links through Quora and Edaboardit basically comes down to Wikipedia:. This can be exploited by the surrounding circuit that compares the responses of eorking transistors operating at different current densities to either cancel out the temperature dependency to create a voltage reference or to linearize the transfer function to create a princupal sensor.

Here is a question for you: Transistors base-emitter diodes have one much closer to 1. And I mean, how does it work internally, how does it output a voltage when temperature changes, etc. Post as a guest Name.