[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:02.70,Default,,0000,0000,0000,,>> In this video, I would like to summarize the function
Dialogue: 0,0:00:02.70,0:00:05.70,Default,,0000,0000,0000,,of the voltage follower or unity gain buffer.
Dialogue: 0,0:00:05.70,0:00:09.92,Default,,0000,0000,0000,,This is basically a non-inverting amplifier with a gain of one.
Dialogue: 0,0:00:09.92,0:00:12.00,Default,,0000,0000,0000,,We run our feedback loop again from
Dialogue: 0,0:00:12.00,0:00:16.14,Default,,0000,0000,0000,,our negative terminal directly to our output voltage like so,
Dialogue: 0,0:00:16.14,0:00:20.85,Default,,0000,0000,0000,,and then will often have a load resistance down from our output voltage.
Dialogue: 0,0:00:20.85,0:00:22.35,Default,,0000,0000,0000,,So, there's our feedback loop,
Dialogue: 0,0:00:22.35,0:00:24.17,Default,,0000,0000,0000,,it's connected directly to V0,
Dialogue: 0,0:00:24.17,0:00:26.66,Default,,0000,0000,0000,,and we're going to put our source on
Dialogue: 0,0:00:26.66,0:00:33.29,Default,,0000,0000,0000,,this other side. Plus minus Vs and Rs that's going into the positive terminal.
Dialogue: 0,0:00:33.29,0:00:37.35,Default,,0000,0000,0000,,In this case, V0 is equal to Vs. Now,
Dialogue: 0,0:00:37.35,0:00:39.03,Default,,0000,0000,0000,,I would want to do such a thing,
Dialogue: 0,0:00:39.03,0:00:41.24,Default,,0000,0000,0000,,we already have Vs on the side.
Dialogue: 0,0:00:41.24,0:00:46.79,Default,,0000,0000,0000,,The main reason is because the current that is going into this terminal is equal to zero.
Dialogue: 0,0:00:46.79,0:00:53.30,Default,,0000,0000,0000,,So, I can put any system over here such as a voltage divider or any other voltage system,
Dialogue: 0,0:00:53.30,0:00:54.48,Default,,0000,0000,0000,,may be a sensor bridge,
Dialogue: 0,0:00:54.48,0:00:57.62,Default,,0000,0000,0000,,and not the impacting the circuit on this side.
Dialogue: 0,0:00:57.62,0:01:02.78,Default,,0000,0000,0000,,This is completely isolated from this side.
Dialogue: 0,0:01:02.78,0:01:07.25,Default,,0000,0000,0000,,No current passes from my input circuit to my output circuit,
Dialogue: 0,0:01:07.25,0:01:08.94,Default,,0000,0000,0000,,and that's why we use this buffer.
Dialogue: 0,0:01:08.94,0:01:12.35,Default,,0000,0000,0000,,So, we have V0 is equal to Vs.
Dialogue: 0,0:01:12.35,0:01:14.34,Default,,0000,0000,0000,,If we wrote that in terms of gain,
Dialogue: 0,0:01:14.34,0:01:17.67,Default,,0000,0000,0000,,we would say that V0 is equal to the gain times Vs,
Dialogue: 0,0:01:17.67,0:01:21.22,Default,,0000,0000,0000,,and in this situation gain is equal to exactly one.
Dialogue: 0,0:01:21.22,0:01:24.08,Default,,0000,0000,0000,,We could also draw a picture like so,
Dialogue: 0,0:01:24.08,0:01:30.99,Default,,0000,0000,0000,,where we can say that Vs was coming in being multiplied by one and coming out as V0.