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>> In this video, I would like to summarize the function

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of the voltage follower or unity gain buffer.

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This is basically a non-inverting amplifier with a gain of one.

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We run our feedback loop again from

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our negative terminal directly to our output voltage like so,

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and then will often have a load resistance down from our output voltage.

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So, there's our feedback loop,

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it's connected directly to V0,

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and we're going to put our source on

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this other side. Plus minus Vs and Rs that's going into the positive terminal.

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In this case, V0 is equal to Vs. Now,

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I would want to do such a thing,

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we already have Vs on the side.

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The main reason is because the current that is going into this terminal is equal to zero.

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So, I can put any system over here such as a voltage divider or any other voltage system,

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may be a sensor bridge,

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and not the impacting the circuit on this side.

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This is completely isolated from this side.

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No current passes from my input circuit to my output circuit,

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and that's why we use this buffer.

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So, we have V0 is equal to Vs.

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If we wrote that in terms of gain,

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we would say that V0 is equal to the gain times Vs,

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and in this situation gain is equal to exactly one.

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We could also draw a picture like so,

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where we can say that Vs was coming in being multiplied by one and coming out as V0.