WEBVTT NOTE This file was exported by MacCaption version 7.0.13 to comply with the WebVTT specification dated March 27, 2017. 00:00:11.386 --> 00:00:14.431 align:center line:-1 position:50% size:43% Now that you know a little bit about the four basic instruments 00:00:14.431 --> 00:00:19.186 align:center line:-1 position:50% size:58% that you'll be using for your lab experiments from Lesson 1, 00:00:19.186 --> 00:00:24.524 align:center line:-1 position:50% size:69% let's now focus on how to properly scale waveforms on the oscilloscope. 00:00:24.524 --> 00:00:31.615 align:center line:-1 position:50% size:66% Hi, I'm Johnnie Hancock, Product Manager for Keysight Technologies InfiniiVision oscilloscopes. 00:00:31.615 --> 00:00:35.994 align:center line:-1 position:50% size:57% Let's pick up where we left off in Lesson 1. 00:00:35.994 --> 00:00:40.999 align:center line:-1 position:50% size:50% Here, you can see our two waveforms from the resistive divider circuit, 00:00:40.999 --> 00:00:46.964 align:center line:-1 position:50% size:53% but you're not likely to walk into your lab and see it already set up for you. 00:00:46.964 --> 00:00:52.010 align:center line:-1 position:50% size:47% In fact, it could be in a very strange setup condition, special modes 00:00:52.010 --> 00:00:56.682 align:center line:-1 position:50% size:44% that one of your fellow students used in the previous lab session. 00:00:56.682 --> 00:01:01.019 align:center line:-1 position:50% size:67% My first recommendation is to press Default Setup. 00:01:01.019 --> 00:01:05.524 align:center line:-1 position:50% size:52% On your scope, it may be called preset or maybe clear. 00:01:05.524 --> 00:01:08.235 align:center line:-1 position:50% size:35% Here's Default Setup here. 00:01:08.235 --> 00:01:13.156 align:center line:-1 position:50% size:54% When we press Default Setup, it's going to go to a standard configuration, 00:01:13.156 --> 00:01:17.869 align:center line:-1 position:50% size:45% and it's not going to be set up right, but it turns off all special modes. 00:01:17.869 --> 00:01:23.166 align:center line:-1 position:50% size:63% After pressing Default Setup, there are three main things you need to adjust: 00:01:23.166 --> 00:01:29.381 align:center line:-1 position:50% size:49% The vertical scaling, the trigger level, and the horizontal. 00:01:29.381 --> 00:01:33.010 align:center line:-1 position:50% size:37% Let's take a closer look at the front panel over here, 00:01:33.010 --> 00:01:39.349 align:center line:-1 position:50% size:46% and those three adjustments are in three sections of the scope. 00:01:39.349 --> 00:01:44.396 align:center line:-1 position:50% size:48% This section here is called the vertical scaling section. 00:01:44.396 --> 00:01:49.359 align:center line:-1 position:50% size:61% It's usually located just above the input/DNCs. 00:01:49.359 --> 00:01:54.323 align:center line:-1 position:50% size:47% Then, there's the horizontal section, that's this top section up here, 00:01:54.323 --> 00:01:59.578 align:center line:-1 position:50% size:44% and the trigger section, and this is the trigger level knob. 00:01:59.578 --> 00:02:04.499 align:center line:-1 position:50% size:62% These two sections, the horizontal and trigger, on different vendors' oscilloscopes, 00:02:04.499 --> 00:02:07.461 align:center line:-1 position:50% size:54% they could be located in different places. 00:02:07.461 --> 00:02:13.008 align:center line:-1 position:50% size:57% My suggestion to you is look at your scope and find those three sections, 00:02:13.008 --> 00:02:15.927 align:center line:-1 position:50% size:41% vertical, horizontal, and trigger. 00:02:15.927 --> 00:02:19.598 align:center line:-1 position:50% size:65% What do we mean by adjust the vertical scaling? 00:02:19.598 --> 00:02:21.475 align:center line:-1 position:50% size:36% Here's the vertical section. 00:02:21.475 --> 00:02:22.684 align:center line:-1 position:50% size:34% There's a big knob there. 00:02:22.684 --> 00:02:27.606 align:center line:-1 position:50% size:65% Some scopes, there are dedicated scaling knobs for each channel. 00:02:27.606 --> 00:02:31.401 align:center line:-1 position:50% size:43% In this particular scope, there's one set of scaling knobs, 00:02:31.401 --> 00:02:34.488 align:center line:-1 position:50% size:42% and they're multiplex, so if I want to adjust Channel 1, 00:02:34.488 --> 00:02:40.702 align:center line:-1 position:50% size:50% I press the 1 button, rotate the knobs, 2, rotate the knobs and so on. 00:02:40.702 --> 00:02:42.454 align:center line:-1 position:50% size:42% Let's adjust the vertical scaling. 00:02:42.454 --> 00:02:45.749 align:center line:-1 position:50% size:42% We can see our sine wave here from the default setup. 00:02:45.749 --> 00:02:49.711 align:center line:-1 position:50% size:48% It's a bit too small, so let's expand it. 00:02:49.711 --> 00:02:51.671 align:center line:-1 position:50% size:35% That's expanded too high. 00:02:51.671 --> 00:02:55.175 align:center line:-1 position:50% size:35% You want it to fill up at least half of the screen. 00:02:55.175 --> 00:03:01.014 align:center line:-1 position:50% size:55% If I click it, then I get a fine increment of adjustment. 00:03:01.014 --> 00:03:06.103 align:center line:-1 position:50% size:50% Click the knob again, I get big jumps. 00:03:06.103 --> 00:03:13.527 align:center line:-1 position:50% size:47% Notice as I'm changing this scaling, this number up here is changing. 00:03:13.527 --> 00:03:16.363 align:center line:-1 position:50% size:50% We'll get back to that in just a minute. 00:03:16.363 --> 00:03:19.783 align:center line:-1 position:50% size:56% The next step is to adjust the trigger level. 00:03:19.783 --> 00:03:26.081 align:center line:-1 position:50% size:59% Triggering is really important, and we're going to get to that in a later lesson. 00:03:26.081 --> 00:03:27.374 align:center line:-1 position:50% size:31% This is the trigger level. 00:03:27.374 --> 00:03:34.297 align:center line:-1 position:50% size:61% As soon as I rotate the knob, a horizontal line pops up and shows me where the level is. 00:03:34.297 --> 00:03:39.261 align:center line:-1 position:50% size:47% If I move it up above the waveform, the scope loses trigger. 00:03:39.261 --> 00:03:44.891 align:center line:-1 position:50% size:47% I haven't explained what that is yet, but all you see is a blur of signals. 00:03:44.891 --> 00:03:51.064 align:center line:-1 position:50% size:46% For now, just set it about the middle of the waveform. 00:03:51.064 --> 00:03:55.193 align:center line:-1 position:50% size:45% The last step in setting up scaling is the horizontal, 00:03:55.193 --> 00:03:57.362 align:center line:-1 position:50% size:37% how is it scaled horizontally. 00:03:57.362 --> 00:04:02.200 align:center line:-1 position:50% size:44% If I rotate this large knob up here in the horizontal section, 00:04:02.200 --> 00:04:07.664 align:center line:-1 position:50% size:50% rotate it clockwise, now it's spreading the signal out, showing less cycles. 00:04:07.664 --> 00:04:10.750 align:center line:-1 position:50% size:34% If I rotate it the other way, it shows more cycles. 00:04:10.750 --> 00:04:16.006 align:center line:-1 position:50% size:67% My suggestion is to get a couple cycles on screen. 00:04:16.006 --> 00:04:21.094 align:center line:-1 position:50% size:56% If you rotate any of these knobs the wrong direction, just go back the other direction. 00:04:21.094 --> 00:04:22.471 align:center line:-1 position:50% size:19% It's very easy. 00:04:22.471 --> 00:04:25.223 align:center line:-1 position:50% size:42% Now, we've got the input signal. 00:04:25.223 --> 00:04:31.980 align:center line:-1 position:50% size:49% This is Channel 1 of the oscilloscope, it's probing on the Vin of our circuit. 00:04:31.980 --> 00:04:36.443 align:center line:-1 position:50% size:44% What about the output, the volage across R2 to ground? 00:04:36.443 --> 00:04:41.156 align:center line:-1 position:50% size:48% Let's turn on Channel 2, so I'm probing it in the proper place, 00:04:41.156 --> 00:04:46.870 align:center line:-1 position:50% size:61% and now we just do exactly like we did before, but now we only need to scale the vertical. 00:04:46.870 --> 00:04:50.999 align:center line:-1 position:50% size:51% The horizontal is already scaled for us, and we're triggering on Channel 1. 00:04:50.999 --> 00:04:53.293 align:center line:-1 position:50% size:41% We don't have to adjust those. 00:04:53.293 --> 00:04:56.922 align:center line:-1 position:50% size:42% Now we just, again, adjust the vertical scaling knob. 00:04:56.922 --> 00:05:00.425 align:center line:-1 position:50% size:54% Again, you can see this number change. 00:05:00.425 --> 00:05:08.808 align:center line:-1 position:50% size:57% Now, you can see the Channel 2 waveform, which is Vout, across R2. 00:05:08.808 --> 00:05:11.770 align:center line:-1 position:50% size:64% Back to those numbers at the top of the screen. 00:05:11.770 --> 00:05:19.945 align:center line:-1 position:50% size:61% Up here, you can see this says 2.00 V/div. 00:05:19.945 --> 00:05:23.406 align:center line:-1 position:50% size:62% It doesn't say division, but that's what it means. 00:05:23.406 --> 00:05:28.495 align:center line:-1 position:50% size:38% That's telling you the scaling of the Channel 1 waveform. 00:05:28.495 --> 00:05:37.087 align:center line:-1 position:50% size:58% We can use that to get an estimate of what the amplitude is of the Channel 1 waveform. 00:05:37.087 --> 00:05:41.466 align:center line:-1 position:50% size:60% Let's see how big is the Channel 1 waveform. 00:05:41.466 --> 00:05:47.347 align:center line:-1 position:50% size:52% I'm going to reposition it a little bit here, position it up here. 00:05:49.391 --> 00:05:51.518 align:center line:-1 position:50% size:41% There are divisions on screen. 00:05:51.518 --> 00:05:53.395 align:center line:-1 position:50% size:32% That's these white lines. 00:05:53.395 --> 00:05:57.941 align:center line:-1 position:50% size:50% The distance between the white lines is called a division. 00:05:57.941 --> 00:06:04.322 align:center line:-1 position:50% size:35% The yellow waveform, Vin, from top of R1 to ground, 00:06:04.322 --> 00:06:09.619 align:center line:-1 position:50% size:38% one, two, three, four, five, it's about five divisions high, 00:06:09.619 --> 00:06:16.501 align:center line:-1 position:50% size:41% times 2 V per division tells you that it's about 10 V pk-pk. 00:06:16.501 --> 00:06:19.045 align:center line:-1 position:50% size:41% That's exactly what we expect. 00:06:19.045 --> 00:06:21.464 align:center line:-1 position:50% size:50% What about the Channel 2 waveform? 00:06:21.464 --> 00:06:27.679 align:center line:-1 position:50% size:60% It looks like it's the same size as the Channel 1 waveform, but it's not really, 00:06:27.679 --> 00:06:36.021 align:center line:-1 position:50% size:54% because the scaling factor says 200 mV per division, or .2 V per division. 00:06:36.021 --> 00:06:42.319 align:center line:-1 position:50% size:51% We can count the number of divisions, one, two, three, four, five, 00:06:42.319 --> 00:06:46.906 align:center line:-1 position:50% size:52% times 200 mV per division is about 1 V. 00:06:46.906 --> 00:06:55.915 align:center line:-1 position:50% size:59% Again, exactly what we expect based on the schematic, the circuit that we're probing. 00:06:55.915 --> 00:06:57.584 align:center line:-1 position:50% size:26% What about timing? 00:06:57.584 --> 00:07:03.048 align:center line:-1 position:50% size:53% This number up here, notice if I change the time scale, this one also changes, 00:07:03.048 --> 00:07:06.676 align:center line:-1 position:50% size:51% tells me what the horizontal scaling is. 00:07:06.676 --> 00:07:09.721 align:center line:-1 position:50% size:43% What is the period of one cycle? 00:07:09.721 --> 00:07:17.103 align:center line:-1 position:50% size:47% I can see that it's about one, two, three, four, five divisions wide, 00:07:17.103 --> 00:07:25.528 align:center line:-1 position:50% size:50% times 10 μs per division tells me that it's 50 μs for one period. 00:07:25.528 --> 00:07:32.035 align:center line:-1 position:50% size:63% If you take the reciprocal of that, that tells you what the frequency is, it's 20 kHz, 00:07:32.035 --> 00:07:38.291 align:center line:-1 position:50% size:52% and that's exactly what I have set as the output of the function generator. 00:07:38.291 --> 00:07:40.835 align:center line:-1 position:50% size:39% I'll let you in on a little secret. 00:07:40.835 --> 00:07:45.256 align:center line:-1 position:50% size:63% There's a special button that you shouldn't use. 00:07:45.256 --> 00:07:47.884 align:center line:-1 position:50% size:28% It's called auto scale. 00:07:47.884 --> 00:07:50.303 align:center line:-1 position:50% size:59% It will automatically set up the scope for you. 00:07:50.303 --> 00:07:55.225 align:center line:-1 position:50% size:63% On your scope, it may be called auto set or something like that. 00:07:55.225 --> 00:07:57.435 align:center line:-1 position:50% size:42% I suggest not using that button. 00:07:57.435 --> 00:07:59.479 align:center line:-1 position:50% size:45% First of all, it doesn't always work. 00:07:59.479 --> 00:08:03.108 align:center line:-1 position:50% size:53% If you have a very low frequency signal, it won't work. 00:08:03.108 --> 00:08:07.487 align:center line:-1 position:50% size:64% If you have a very complex signal, it won't work. 00:08:07.487 --> 00:08:11.574 align:center line:-1 position:50% size:46% Most of all, you're not going to learn how to use the oscilloscopes. 00:08:11.574 --> 00:08:15.578 align:center line:-1 position:50% size:48% Your professors or lab coordinators, 00:08:15.578 --> 00:08:18.832 align:center line:-1 position:50% size:51% there's a command that they can download into the scope 00:08:18.832 --> 00:08:22.794 align:center line:-1 position:50% size:48% that they can get from our company that disables that button 00:08:22.794 --> 00:08:25.797 align:center line:-1 position:50% size:53% so that you learn how to use the scope. 00:08:25.797 --> 00:08:31.928 align:center line:-1 position:50% size:65% You've now got the basics on how to set up your oscilloscope and properly scale waveforms. 00:08:31.928 --> 00:08:36.266 align:center line:-1 position:50% size:54% We also covered how to make quick estimated measurements of your signals 00:08:36.266 --> 00:08:42.439 align:center line:-1 position:50% size:55% by counting divisions and multiplying by vertical and horizontal scaling factors, 00:08:42.439 --> 00:08:44.983 align:center line:-1 position:50% size:33% which was the only way they could be performed 00:08:44.983 --> 00:08:49.112 align:center line:-1 position:50% size:43% back when I was studying electrical engineering in college. 00:08:49.112 --> 00:08:51.406 align:center line:-1 position:50% size:40% Later during this video series, 00:08:51.406 --> 00:08:56.536 align:center line:-1 position:50% size:65% we'll talk about better and more automated ways to perform measurements on your waveforms. 00:08:56.536 --> 00:09:02.959 align:center line:-1 position:50% size:57% In our next lesson, Lesson 3, we need to take a step back and talk about probing. 00:09:02.959 --> 00:09:07.672 align:center line:-1 position:50% size:62% How do we get the signal into the oscilloscope in the first place? 00:09:07.672 --> 00:09:13.928 align:center line:-1 position:50% size:70% Remember, Keysight has lots of technical resources on oscilloscopes for engineering students 00:09:13.928 --> 00:09:18.433 align:center line:-1 position:50% size:44% that you can download at the URL listed on your screen. 00:09:18.433 --> 00:09:22.937 align:center line:-1 position:50% size:49% One of those resources is this poster that you can download. 00:09:22.937 --> 00:09:28.193 align:center line:-1 position:50% size:46% This poster summarizes what we just covered in Lesson 2. 00:09:28.193 --> 00:09:33.907 align:center line:-1 position:50% size:62% You might want to talk your lab coordinator in to hanging this poster up in your circuits lab, 00:09:33.907 --> 00:09:39.204 align:center line:-1 position:50% size:64% or, if you're a super engineering geek, you might want to hang it up in your dorm room. 00:09:39.204 --> 00:09:41.080 align:center line:-1 position:50% size:45% Nothing wrong with being a geek. 00:09:41.080 --> 00:09:44.626 align:center line:-1 position:50% size:43% Without us geeks, this would be a pretty dim world. 00:09:44.626 --> 00:09:46.503 align:center line:-1 position:50% size:29% See you in Lesson 3. 00:09:46.503 --> 00:09:49.881 align:center line:-1 position:50% size:42% Go North Carolina A&T Aggies!