Description.

Here is a straight forward, yet effective digital temperature controller that can be used with temperature control systems.

The circuit uses IC LM 35 (IC3) to as the temperature sensor. The output of LM 35 is given to the IC ADC 0804 (IC4) which converts the analog output of the LM 35 to digital output. The ADC 0804 is a 8 bit ADC. Eight LED’s are connected to the output  of ADC to show the output logic. If needed the LED’s can be avoided and the output can be connected to any suitable external circuit like temperature controller etc. A 5V fixed voltage regulator based on 7805 (IC1) powers the circuit. Another variable voltage regulator based on LM317 (IC2) is used to provide the reference voltage to the ADC 0804.

Circuit diagram with Parts list. 

Digital Temperature Sensor Circuit
Digital Temperature Sensor Circuit

Notes. 

  • POT R10 can be used to adjust the scale factor of the ADC.The reference voltage at pin  7 of ADC0804 should be 2.5 V for full scale.
  • Assemble the digital circuit project on a good quality PCB or common board.
  • If 1A bridge is not available make one with four 1N 4007 diodes.
Author

29 Comments

  1. FIKADU DIRIBA

    thank u i am student pleace how i get the progeram of oil immersed distrubution transformer temperature sensor LM35 AND drive fan in micro c progeram

  2. In ckt lc lm317 is used in which pin no1 is input but in datasheet pin no 3 is input.then what we take.

  3. At output we get logic from eight led. But what is
    that logic.

  4. i want connection for lm35 with adc0804 then that output given to encoder dow can i do this connection please help me

  5. ganesh waysal

    hallo,
    i want to make temperature controller so please send me how to interface adc 0804 with 8051 using LM 35,and also send its ALP prgramming.
    i’m very thankful to you.

  6. raj kumar sharma

    hi,
    i want to make aanalog to digital convertor with

    usb so i want your guide lines to make acircuit

    diagram .

  7. Hello,plz someone help me,,am working on this circuit,,plz send me the simulation of this circuit on proteus,plz

  8. hi sir
    please heeeeeeeeelllllppppppppppp meeeeeeeeeee
    I also need the detail of the component used after the bridge (AC 230V) It has the symbol of a transformer but i am not sure at all. please help me out.
    Thanks

  9. I need the detail of the component used after the bridge (AC 230V) It has the symbol of a transformer but i am not sure at all. please help me out.
    Thanks

    • Hello,please send me the simulation of this circuit on Proteus,plz plz plz……….am very thankful to you

  10. Voice Recorder

    Some neat info you have here, excellent work !!!

    • Hello,please send me the simulation of this circuit on Proteus,plz plz plz

  11. Hi i am actually using this circuit in my assignment. i am doing my circuit in Proteus. is there any need to connect pin8,10 and 20?
    I also need the detail of the component used after the bridge (AC 230V) It has the symbol of a transformer but i am not sure at all. please help me out.
    Thanks

  12. yarra vijay

    this site is very useful for learning of electronic basics

  13. seetharaman

    Hi Shaban and Vysakh please communicate in english such that others can also use your valuable information.

  14. ﺎﻨﻫ ﻞﻀﻔﺑ ﻱﺃ ﻰﻟﺇ ﺝﺎﺘﺤﺗ ﻻ

  15. واعاملين شكر جدا جداشكرا جزيلا لكل القائمين على الموقع

    • hello,plz help me,am working on this circuit,,plz send me the simulation of this circuit on proteus,,am very thank ful to you

  16. واعاملين شكر جدا جداشكرا جزيلا لكل القائمين على الموقع

  17. please i need full description of the circuit. thanks

  18. plz put full description, I got problem in the simulation ?
    pin number 20 is connected to where? also 8 and 10 ? for pin number 7 need to connect to -2/5 or +2/5 ?
    i simulated in proteus but i can’t get the result plz describe it if is possible
    thanks alot

  19. hi it seems to be a good circuit for ADC can you send us more information about circuit. thanks alot

  20. rubana shaikh

    requaire full discription of circuit diagram

  21. i want to make this circuit can you help me…………….

  22. chandrashekar

    Its very good site for electronics persons and i like very much this site.

    Thanks for providing imformation