Set any minimum and maximum temperature with the help of LCD display, by pressing switches S2 and S3. The maximum temperature will start from minimum temperature +10 degrees. If the temperature being measured is more than the preset maximum temperature, relay RL1 de-energises and the heating element is switched off. Similarly, when the measured temperature goes below the preset minimum temperature, relay RL1 is energised and the heating element is turned on.

To check the circuit for proper functioning, verify 5V power supply at TP1 with respect to TP0. TP2 is ‘low’when temperature goes below minimum temperature and remains in that state until the maximum temperature is reached.

The author is a B.Tech (electronics engineering) from Dr A.I.T., Bengaluru


  1. Hello. Question about the programming. I tried to program the PIC with ICprog and JDM programmer, but i’m getting verifying error after data verification. Can You suggest me something?

  2. You can burn the code using any equivalent programmer. During testing we had used PICStart Plus Programmer with MPLAB software.

  3. Hiii Sir.
    In this Proect I also want to control temperature under COOLING Atmosphere so what i should use here as a Cooling Junction instead of Heating Element??

    Can I use Any other Simple Instrumentaion Amp instead of using Thermal INSTRUmentaion Amplifier..

    also I will be more Gladful if I receive any operating Video of this Project…
    Thank You for Your warm responce….

    My email id IS : [email protected]

  4. sir,
    whether LM35 sensor can be used in the place of IC2-AD8495 and K-type thermocouple ??…is there any other similar circuit diagram for this same temperature controller project using LM35?

  5. hello sir pls tell me what is thebest pragraming txt book if you have pls send to me iam new for programing to embed

  6. Thanks for the post sir.
    Can i use lm35dz instead of the k type thermocouple?
    If.yes, how can i connect the lm 35dz pin to the circuit?
    Thank you.

  7. I have been trying to get the source code for this project and failed several times and asking if its possible to email it or buying already programmed micro-controller.

  8. Hi Sunil ,

    Sanjeev this side from Frigoglass we required one temperature indicator with six display

    can u please guide us for same


  9. Hello sir please am using proteus to draw the circuit and stimulate but I couldn’t get the relay and the k-type thermocouple on its can you help with that sir happy if I would get a quick response to that

  10. Hello I drew the circuit using a proteus software but couldn’t get the k type thermocouple and relay used can you help with that

  11. Heater Electric 1000 watt Converter OR Controller 01
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    e-mail : [email protected]

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  12. There is a problem accessing source code, none of the provided links or download sites give access to any code. By the look of the other comments lots of people are experiencing same difficulty, and none of your suggestions work. Whats the story.

    • Hi Geoff, the source code is present within the article, just click and download. If you are not able to download the code, please temporarily turn off the antivirus and then redownload.


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