Anyone have an idea to convert 0.6V - 1.3V to 0-5V with high sensitivity

Discussion in 'The Projects Forum' started by nlmardhiah, Jun 2, 2016.

  1. nlmardhiah

    Thread Starter New Member

    Mar 17, 2016
    4
    0
    Hye Experts,

    Anyone can help me on this problem...
    I want to amplify my milivolt signal from 640mV to 1300mV to 0-5V with high sensitivity.
    Currently i already tried to amplify but I can't get the output nearest or close to the range 0-5V..
    what i get is from 2.8V to 4.8V..Anyone can give me an idea how to amplify my input n get the min output close 0.9 or 1V & max ouput close to 5 such 4.7, 4.8 or 4.9...Pls ..really need your idea so that I can study further on that & achieved my objective...huhuhu
     
  2. ericgibbs

    AAC Fanatic!

    Jan 29, 2010
    2,501
    380
    hi,
    This is one option.
    Note: even with a rail to rail OPA, at 5Vsupply the maximum Vout will always be just under 5v.
    Try a 6V supply.
    E
     
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  3. nlmardhiah

    Thread Starter New Member

    Mar 17, 2016
    4
    0
    Hye Sir,

    Really appreciate your help...Its looks work....thankk you soo much for ur help...
    But, may I know what type of op-amp did you use for U1, U2 and U3.. or can u suggest any model of op-amp to me?
     
  4. AlbertHall

    Well-Known Member

    Jun 4, 2014
    1,908
    379
    You could use an open collector output op-amp, for instance LM393, where the output voltage can reach the supply voltage.
     
  5. DickCappels

    Moderator

    Aug 21, 2008
    2,649
    632
    Can you post your existing circuit so we can see what is giving you the problem(s)?

    Please include the power supply voltage(s).
     
  6. ericgibbs

    AAC Fanatic!

    Jan 29, 2010
    2,501
    380
    hi,
    The LM393 is an open collector output comparator.

    @nlmardhiah
    Use a MCP6002 dual OPA.
    If you use a MCP6002, note the max Vsupply is +5.5v
    E
     
  7. nlmardhiah

    Thread Starter New Member

    Mar 17, 2016
    4
    0
    Hi Sir,

    Thanks for the idea.
    I already try to built the cct on breadboard with op-am (U1 & U2) MCP6002. But some error occured.
    So, can I confirm back the value that use for the each component =)

    From the figure that you give :
    C1 : 1u
    R5 : 820
    U3 : 10kpotzero
    R4 : 2k
    R3 : 14k
    R7 : 2k
    R6 : 4k
    C2 : 100n
    C3 : 47u

    Really appreciate your help =(
    Tq.
     
  8. ericgibbs

    AAC Fanatic!

    Jan 29, 2010
    2,501
    380
    hi,
    Those values are almost correct and the circuit should work OK, note that R3 is a 20k pot to set the Gain.
    Note, the 'k' between the value numbers is used as a decimal point ie: 2k2 =2.2k

    What is the error.??

    E
     
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