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Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:02.73,Default,,0000,0000,0000,,>> In this video, I would like to summarize
Dialogue: 0,0:00:02.73,0:00:06.06,Default,,0000,0000,0000,,the characteristics of a non-inverting op-amp amplifier.
Dialogue: 0,0:00:06.06,0:00:08.64,Default,,0000,0000,0000,,Remember that we start with a basic op-amp like this
Dialogue: 0,0:00:08.64,0:00:11.26,Default,,0000,0000,0000,,and it has an output voltage coming out like so.
Dialogue: 0,0:00:11.26,0:00:12.68,Default,,0000,0000,0000,,Whenever we have feedback,
Dialogue: 0,0:00:12.68,0:00:15.72,Default,,0000,0000,0000,,it goes from the negative terminal towards the output.
Dialogue: 0,0:00:15.72,0:00:20.68,Default,,0000,0000,0000,,In this case, we're going to run it across two resistors R1 and R2,
Dialogue: 0,0:00:20.68,0:00:22.56,Default,,0000,0000,0000,,down to ground and that gives us
Dialogue: 0,0:00:22.56,0:00:25.72,Default,,0000,0000,0000,,the negative feedback to the output voltage that's right here.
Dialogue: 0,0:00:25.72,0:00:27.82,Default,,0000,0000,0000,,The input voltage Rs,
Dialogue: 0,0:00:27.82,0:00:34.24,Default,,0000,0000,0000,,is going to run through a resistance Rs to the positive terminal as shown here.
Dialogue: 0,0:00:34.24,0:00:36.96,Default,,0000,0000,0000,,In the case of a non-inverting op-amp amplifier,
Dialogue: 0,0:00:36.96,0:00:43.86,Default,,0000,0000,0000,,V0 is equal to Vs times R1 plus R2 divided by R2.
Dialogue: 0,0:00:43.86,0:00:48.16,Default,,0000,0000,0000,,There are several things to also remember about this non-inverting op-amp, for instance,
Dialogue: 0,0:00:48.16,0:00:52.46,Default,,0000,0000,0000,,that it is powered by two voltages plus Vcc and minus
Dialogue: 0,0:00:52.46,0:00:58.43,Default,,0000,0000,0000,,Vcc that limit the possible range of V0 between them.
Dialogue: 0,0:00:58.43,0:01:01.50,Default,,0000,0000,0000,,These are often called the rail voltages.
Dialogue: 0,0:01:01.85,0:01:06.17,Default,,0000,0000,0000,,In addition, let's take a look at this thing as gain.
Dialogue: 0,0:01:06.17,0:01:08.78,Default,,0000,0000,0000,,We often will write that V0 is equal to
Dialogue: 0,0:01:08.78,0:01:12.95,Default,,0000,0000,0000,,the gain times Vs and for the case of the non-inverting op-amp,
Dialogue: 0,0:01:12.95,0:01:17.58,Default,,0000,0000,0000,,the gain is R1 plus R2 divided by R2.
Dialogue: 0,0:01:17.58,0:01:20.39,Default,,0000,0000,0000,,Notice, that this is a positive value.
Dialogue: 0,0:01:20.39,0:01:22.52,Default,,0000,0000,0000,,That's why it's a non-inverting op-amp.
Dialogue: 0,0:01:22.52,0:01:26.46,Default,,0000,0000,0000,,Also, notice that it is greater than or equal to one.
Dialogue: 0,0:01:26.46,0:01:28.44,Default,,0000,0000,0000,,The only way it could be equal to one,
Dialogue: 0,0:01:28.44,0:01:31.80,Default,,0000,0000,0000,,is if R1 was zero which in fact it could be.
Dialogue: 0,0:01:31.80,0:01:37.07,Default,,0000,0000,0000,,So, this is the case for a positive gain op-amp amplifier.
Dialogue: 0,0:01:37.07,0:01:38.52,Default,,0000,0000,0000,,We can never reduce the voltage,
Dialogue: 0,0:01:38.52,0:01:40.12,Default,,0000,0000,0000,,we only can increase it.
Dialogue: 0,0:01:40.12,0:01:43.94,Default,,0000,0000,0000,,Another way that we might represent this amplifier would be to say
Dialogue: 0,0:01:43.94,0:01:47.84,Default,,0000,0000,0000,,that Vs is coming into the amplifier and is being
Dialogue: 0,0:01:47.84,0:01:51.34,Default,,0000,0000,0000,,multiplied by the gain and that is giving us
Dialogue: 0,0:01:51.34,0:01:57.54,Default,,0000,0000,0000,,the V0 value and that the gain is always greater than or equal to one.