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