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For some reason Op-Amps are impossible for me. I'm experimenting with them a little bit. I have the following circuit...

schematic

simulate this circuit – Schematic created using CircuitLab

This is the circuit I have on my breadboard. I was just trying to see the "infinite gain" I would expect from this configuration.

The inverting input is around 4.5v, while the non-inverting input is at ground. I should be achieving my maximum potential (Limited by the power rail.) I.E. around 9V at the output, but I'm recieving .6v?

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  • \$\begingroup\$ The LM386 is not an op-amp - it is an audio power amplifier with built-in feedback network to control the gain. It will not operate as a "normal" op-amp. \$\endgroup\$
    – Peter Bennett
    Commented May 13, 2015 at 6:34

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You've connected your inputs backwards. A higher voltage on the non-inverting input produces a more positive output. You put the higher voltage on the inverting input, so the op amp output goes as low as it can. In this case, that's close to ground.

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  • \$\begingroup\$ You're right. Still only getting around 8v though? Checked the battery output. Solid at 8.8V. \$\endgroup\$
    – Allenph
    Commented May 13, 2015 at 3:41
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    \$\begingroup\$ Just as the output in your first version was trying to drive below zero, but could only get down to 0.6, now you're trying to drive as high as possible but the op amp will not get closer than 0.8 volts from the positive supply. \$\endgroup\$
    – WhatRoughBeast
    Commented May 13, 2015 at 4:14

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