I don't know why I cannot operate Op-Amps! this is my second circuit and I'm trying to make a non-inverting amplifier by an OP07CP. This is my circuit + an example of measured values:


simulate this circuit – Schematic created using CircuitLab

And when I applied 0v to the +input, I got -5.47v in the output. and again for 17.9mv, I got 1.78v. when I change the supply to 0-5v, I just get an amount around 4.5v or 1.5v. I'm harassed! I expected to get 3153.969mv in the output when I applied 9.1mv but as you can see, I just got -1.15!(when supply is -12 - +12). Why doesn't it work correctly? Can I operate this Op-Amp with 0-3.3v or 0-5v supply? how?

  • 2
    \$\begingroup\$ The OP07 is specified to run from a minimum supply voltage of 6V. \$\endgroup\$
    – Andy aka
    May 3, 2015 at 17:19
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    \$\begingroup\$ Good on you for linking a datasheet, but it's best to link straight to the version on the manufacturers website. \$\endgroup\$
    – Matt Young
    May 3, 2015 at 18:38

2 Answers 2


Your schematic is wrong. V2 should either be +11.75V or you should flip it.

The circuit (with +/-12V-ish supplies) should work. However, you've got an offset pot- it can adjust the input offset to +/-4mV typically. If you crank it all the way down, the input can appear to be 9mV - 4mV = 5mV. Nominal gain is about 350, so this still appears to be off. You might want to parallel R2 with a small capacitor (10nF ceramic, for example) in case the op-amp is oscillating (if you have an oscilloscope, look at the output directly). Leave out the offset pot to begin with- even the cheap version is within 150uV Vos without the pot. Bypass the supplies too, near the op-amp.

The OP-07 is an ancient 'precision' op-amp with a distinguished and storied past, however it's not a rail-to-rail input or output or even a single supply op-amp. It is possible to run it from +/-5V (with some care) but not (reliably) from 0/5V.

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    \$\begingroup\$ I changed it to +11.75. Thanks and your answer was great! I put a 10nF in parallel to R2! oh, it's now better(about 300mv). let's to put a 100nF between 0 and positive rail. oh! again it's better. I cranked the pots to adjust the offset and I got 3.1v as I expected! let's to put a 100nF between 0 and negative rail. oh, it's a teeny bit reduced(it's 3v). Perfect! Thank you! \$\endgroup\$
    – Roh
    May 3, 2015 at 17:41
  • \$\begingroup\$ Actually, it's rated to +/- 3 volts, so a limited operation with a single 6 volt supply is OK. 0-5 is entirely possible (although extremely device-dependent), but a single 3.3 volt supply is pretty much guaranteed not to work. \$\endgroup\$ May 3, 2015 at 18:38
  • \$\begingroup\$ @WhatRoughBeast Yes, both statements are true. 0/5V is probably 'possible' over a limited temperature range with most, if not all, devices, but I don't think we should encourage that sort of thing, particularly at an early stage of learning. Look in the datasheet. Understand the datasheet. Respect the limits. Understand why the limits are there from the internal operation. Then he or she can consider bending the rules if the circumstances permit. \$\endgroup\$ May 3, 2015 at 19:23

Your R4 is wired strangely. If you turn it to zero, you short out your V1 supply. R3 Suffers the same problem if R4 is all the way up.


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