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>> In this video, I would like to summarize
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the characteristics of a non-inverting op-amp amplifier.
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Remember that we start with a basic op-amp like this
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and it has an output voltage coming out like so.
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Whenever we have feedback,
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it goes from the negative terminal towards the output.
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In this case, we're going to run it across two resistors R1 and R2,
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down to ground and that gives us
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the negative feedback to the output voltage that's right here.
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The input voltage Rs,
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is going to run through a resistance Rs to the positive terminal as shown here.
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In the case of a non-inverting op-amp amplifier,
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V0 is equal to Vs times R1 plus R2 divided by R2.
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There are several things to also remember about this non-inverting op-amp, for instance,
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that it is powered by two voltages plus Vcc and minus
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Vcc that limit the possible range of V0 between them.
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These are often called the rail voltages.
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In addition, let's take a look at this thing as gain.
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We often will write that V0 is equal to
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the gain times Vs and for the case of the non-inverting op-amp,
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the gain is R1 plus R2 divided by R2.
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Notice, that this is a positive value.
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That's why it's a non-inverting op-amp.
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Also, notice that it is greater than or equal to one.
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The only way it could be equal to one,
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is if R1 was zero which in fact it could be.
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So, this is the case for a positive gain op-amp amplifier.
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We can never reduce the voltage,
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we only can increase it.
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Another way that we might represent this amplifier would be to say
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that Vs is coming into the amplifier and is being
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multiplied by the gain and that is giving us
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the V0 value and that the gain is always greater than or equal to one.
