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little problem with lm35

Discussion in 'General Electronics Chat' started by be80be, Jan 11, 2018.

  1. be80be

    be80be Well-Known Member

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    I just read the datasheet for maybe the 100 time in my life but the lm35 is really a 4 to 30 volt chip datasheet did say 4 to 5.5 at one time they changed that.
    This is my problem I hook it up thinking what the heck I can get away with 3.3 volt supply nope that gives way lower reading then using a 5 volts supply.

    So I read the data sheet and it said the lm35 can output a max of 6 volts if supply is high enough well 5 volt a guess maybe 4.3 high max
    But I don't see it going over maybe a 1 volt max.

    So I should be ok with it using 5 volt as long as the output never goes over 3.3 looks like that would never happen at 0 to 30c
     
  2. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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    hi be80.
    As you know the LM35 is rated for a single supply of 5V, to work from +2C thru +150C, at 10mV/C change.
    So that's 150 * 0.01V = 1.5V
    Eric
     
    • Agree Agree x 1
  3. be80be

    be80be Well-Known Member

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    That was my take too that it never get above 1.5 O figure maybe more like 1 volt Im never going to heat my house to 150C lol

    Maybe 26 to 28 c
    Now to figure where I can get 5 volts easy the board only has 3.3 broke out .
     
  4. dave miyares

    Dave New Member

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  5. dr pepper

    dr pepper Well-Known Member Most Helpful Member

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    A 7660 will double the volts for you with just a few caps and the chip.
     
  6. be80be

    be80be Well-Known Member

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    Screenshot from 2018-01-12 10-50-17.png
    Something like this
     
  7. dr pepper

    dr pepper Well-Known Member Most Helpful Member

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    Well found Burt.
    Yes very much like that.
     

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