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I want to use famous 741 ic to amplify the voltage from a sensor which is in the range 0-50 mV to 0-5V but the problem is all the circuits I found on web use +/- supply but i want to use only 5V supply from arduino so no negative voltage. Which configuration i need to use for a gain of 100? When input is 0, output should be zero when input is .1mV output be 10 mV...if 741 is not feasible, suggest alternate ICs with single supply that accept such low voltages

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    \$\begingroup\$ Google "single supply low voltage rail-to-rail op amp". See, for example, ti.com/lit/ds/symlink/lmv321-n.pdf \$\endgroup\$ Commented Nov 12, 2015 at 2:33
  • \$\begingroup\$ For low DC input voltages you need a "rail to rail" op amp. Traditional op amps need > ~0.7 on the input due to the IC using a BJT transistors instead of FET ones. \$\endgroup\$
    – MadHatter
    Commented Nov 12, 2015 at 2:41
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    \$\begingroup\$ You probably needs a better Opamp. Today are good Opamp with low price. As @AlfredCentauri said search for a single supply configuration and an Ampop with low voltage offset and rail-to-rail output. \$\endgroup\$ Commented Nov 12, 2015 at 2:50
  • \$\begingroup\$ You could use a 741 with a single supply, but it would have to be 10V or more - the 741 is not specified to run at lower voltages than this, and it won't then deal with input or output voltages close to GND - as others say, use a newer, better op-amp - there are rail-rail input and output op-amps that will operate at 5V \$\endgroup\$
    – Icy
    Commented Nov 12, 2015 at 8:25
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    \$\begingroup\$ You have two mutually contradictory requirements : 0V rail to 5V rail operation, and the 741. One of these requirements MUST go. Which, is entirely up to you. \$\endgroup\$
    – user16324
    Commented Nov 12, 2015 at 11:45

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You cannot use a 741 with a 5 volt power supply. The chip simply is not rated for voltages that low. About the lowest you can go is a +/- 5 volt supply, and even then, the output would only produce an output range of about +/-2 to +/- 3 volts.

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  • \$\begingroup\$ And nice as it sounds you can never actually get 0-5V output if all you have is 0 and 5V supplies, new devices can get very close but the 741 is not in the ballpark. \$\endgroup\$
    – KalleMP
    Commented Nov 12, 2015 at 9:00

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