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0-10V, 4-20mA conversion to 0-5V

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by leonel, Aug 30, 2005.

  1. Gazza_AU

    Gazza_AU Member

    Joined:
    Mar 24, 2017
    Messages:
    37
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    0
    Location:
    AU
    I have never used SMD components.
    Have you ever hand soldered surface mount resistors?
    Been looking for high tolerance resistors for voltage divider and op-amp.

    Found these Thin Film Resistors - SMD RN 0805 49R9
    0.1% 10PPM - $0.41.
    http://au.mouser.com/ProductDetail/TE-Connectivity-Holsworthy/RN73C2A49R9BTD/?qs=sGAEpiMZZMtlubZbdhIBIFho3SHfDXStxrXRNS3VAgQ=



    Can you get better quality for cost in SMD, being so common now?
    What do you think of these resistors for divider and bias circuit.
    ------

    For 5v Reference
    I am not certain how % Initial Accuracy and PPM/C play out in real world use.
    ============
    5v
    1ppm = 0.000005
    10ppm = 0.00005
    -
    10C to 50C = 40C differential Temp.
    40C differential in temperature x 0.00005 = 0.002
    -
    0.02% = 4.999v to 5.001v
    ============
    Suggests 0.02% Initial Accuracy would be similar to 5ppm over the 40C differential Temp range. 10ppm was just a component price break.

    What would create the larger inaccuracy in the real world.
    What %/Accuracy ppm/C ratings ratio would give the best real world Accuracy?
    Wondering how much more Accuracy I get for the higher cost IC?
    ----

    MAX6126A21+
    5v 0.02% Initial Accuracy
    3 PPM / C
    $5.99

    This could do the op-amp bias ref and Arduino Aref pin.
    I would like to find a more affordable ref if possible, but it is an option.

    http://au.mouser.com/ProductDetail/Maxim-Integrated/MAX6126A21+/?qs=sGAEpiMZZMuBck1X%2b7j9fB2T4ftaG3guOyx5Ymmp6ys=
    DataSheet: http://www.mouser.com/ds/2/256/MAX6126-88935.pdf

    Or;
    MAX6250ACSA+
    5v 0.02% Initial Accuracy
    2 PPM / C
    $9.17

    http://au.mouser.com/ProductDetail/Maxim-Integrated/MAX6250ACSA+/?qs=sGAEpiMZZMuBck1X%2b7j9fB2T4ftaG3guusM4a1A2rpc=
    DataSheet: http://www.mouser.com/ds/2/256/MAX6225-MAX6250-87956.pdf
     
    Last edited: Apr 28, 2017

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