Op Amp Gain | Details Calculations Formulas

Operational amplifiers are used in many circuits - one of the main applications is in amplifiers. Here the operational amplifier gain is of key importance.

Although there are both inverting and non-inverting amplifiers which have their own calculations, there is a generic equation for these circuits. The generic formula can be used to develop the equations for the inverting and non-inverting configurations.

The gain of these operational amplifier circuits is governed by the level of negative feedback. Applying negative feedback provides a defined level of gain, wider bandwidth, lower distortion as well as a number of other advantages. However it is often the operational amplifier gain that is of major importance.

When looking at the inverting amplifier circuit, the equation for the circuit can be calculated from the simple formula Av = R2/R1.

For the non-inverting amplifier the gain is slightly different and can be calculated from the formula Av = 1+ (R2/R1).

It is also possible to use the non-inverting amplifier as a buffer amplifier with a unity voltage gain by looping the output back to the inverting input, i.e. R1 = infinity and R2 = zero. In this way the voltage gain can be calculated to be 1.

So in summary both inverting and non-inverting amplifier gain is easy to calculate using the simple formulas.

[MineWiz]

My professor wasted the whole entire classtime deriving the gain formulas and by the end of it I was exausted and didn't even know what an Op Amp did. Thanks for making this so simple.

[arsalan_s]

One of the most beautifully explained opamps videos ever. Cheers to the creator🥂

[goofypettiger]

Thumbs up, dude. A couple things worth pointing out:

1. No current flows into the inputs
2. Voltage difference between inputs is zero

Based on #1 above, we see that the non-inverting amplifier does not draw current from the input source. The inverting amplifier does draw current. So even though the ideal op-amp has "infinite" impedance, in inverting mode, that is no longer the case. This could be an issue for a source that has limited current capability.

[murtadha]

This has been immensely helpful, THANK YOU!!

[Egg]

I like how in my circuits class my professor keeps referring to gain and makes no explanation of what it is. Thankfully there is youtube.

[matambale]

@3:10 - how we can turn the amp up to 11

[ExpertCMX]

Thought this was one of them ridiculous Hindi videos with not even subtitles 😍

[j.m]

Sir, You are great! So thankful for this video.

[ghorabih]

From a circuit analysis point of view, how does one come to the value of 1+(R2/R1) for the gain of a noninverting op amp ?

[CameronTacklind]

Where can I see more about the "and many more things" circuit at 0:15?

[humanityfirst]

Sir what is the nearly gain of operatioal amplifier?

[darkvader]

many thanks for the amazing video it been great help

[evilaugust]

If i want to try a mod on a low pass filter circuit, in order to increase gain, the change on r1 and r2 also changes the low pass frequence? Should i lower r1 or increase r2, if i want to increase gain? Can i use a pot in series with r2? Thanks.

[sash]

Wrong symbol decleration of inverting and non inverting

[stingerbold]

Is it possible to give 100% feedback on inverting amplifier without any resistor Because i want to make stereo power amplifier to bridge mode

[robertbeech]

Great video subbed and pinged that bell!

[guitarguy]

How to make an adjustable gain control should I use only potential meter instead of R2 or pot with series resistor

[stud_mechatronic_polito_]

What's the difference between "amplification" and "gain" of an operational amplifier? Thank you in advance 4 your attention!

[Jarrod_C]

why have a unity gain buffer, i never understood

[meriamsdk]

hey! plz can u help me on how to Design and simulate an inverting amplifier with a gain of 150???
plz help