1 00:00:00,480 --> 00:00:01,100 Welcome back. 2 00:00:01,110 --> 00:00:10,050 In this lesson we shall give an overview of what an ADC or an analog to digital converter is analog 3 00:00:10,050 --> 00:00:18,210 to digital converters are among the most widely used devices for data acquisition digital computers 4 00:00:18,210 --> 00:00:20,780 use binary or discrete values. 5 00:00:21,240 --> 00:00:30,030 But in the physical world everything is analog or continuous temperature pressure humidity velocity 6 00:00:30,470 --> 00:00:35,520 are just a few examples of physical quantities that we deal with every day. 7 00:00:35,800 --> 00:00:44,460 A physical quantity is converted to electrical signals using a device called transducer and a transducer 8 00:00:44,610 --> 00:00:53,010 simply converts a physical quantity to Edo voltage or current transducers used to generate electrical 9 00:00:53,100 --> 00:01:02,610 output are referred to us same source same source for temperatures velocity pressure light and many 10 00:01:02,610 --> 00:01:04,620 other natural physical quantities. 11 00:01:04,740 --> 00:01:10,050 Produce an output that is voltage or sometimes current. 12 00:01:10,260 --> 00:01:17,790 Therefore we need an analog to digital converter to translate the analog signals to digital numbers 13 00:01:18,060 --> 00:01:23,950 so that the microcontroller can read and process these numbers. 14 00:01:23,970 --> 00:01:32,790 Now let's talk about the concept of HD you resolution and ATC has in bit resolution where end can be 15 00:01:32,880 --> 00:01:37,860 eight ten twelve sixteen or even twenty four so you hear. 16 00:01:38,250 --> 00:01:46,350 So you hear of people saying this HD is 10 bit as twelve bit as sixteen bit higher resolution HD provide 17 00:01:46,410 --> 00:01:54,660 a smaller step size where step size is the smallest change that can be detected by an ADC this table 18 00:01:54,690 --> 00:02:01,590 over here shows the number of steps as well as the step size given the number of bits the ABC has so 19 00:02:01,590 --> 00:02:07,480 for instance an AIDS bit ADC would have 256 steps and how do we know this. 20 00:02:07,530 --> 00:02:15,210 We simply do two to the power eight and we get 256 and to compute the step size we've got to take the 21 00:02:15,210 --> 00:02:22,230 reference voltage into account to assume assuming the reference voltage is fivefold we simply do five 22 00:02:22,230 --> 00:02:30,220 divided by 256 and this gives us nineteen and this gives us nineteen point five three million old at 23 00:02:30,240 --> 00:02:40,570 ten but ADC has 1024 step size and the smallest change this 10 bit adc can detect as four point eighty 24 00:02:40,590 --> 00:02:49,350 eight million old in the same way at 12 but ADC has four thousand and ninety six number of steps and 25 00:02:49,350 --> 00:02:57,720 a smallest change this adc can detect is a change in one point two million votes a sixteen bit ADC would 26 00:02:57,720 --> 00:03:04,470 have sixty five thousand five hundred and fifty six steps and the smallest change this ADC will be able 27 00:03:04,470 --> 00:03:13,200 to detect will be zero point zero seven six million vote v ref is an input voltage use for the reference 28 00:03:13,200 --> 00:03:19,920 voltage devoted connected to this pin most microcontrollers have the fear of bean and we can connect 29 00:03:20,430 --> 00:03:28,830 our own input for two or we can just say use the same voltage as the one used by the MCU so the voltage 30 00:03:28,830 --> 00:03:36,150 connected to the V ref been along with the resolution of the ADC chip determine the step size as you 31 00:03:36,150 --> 00:03:44,490 can see over here so assume in our view ref is 5 vote and the resolution of the IT ADC is 8 bit then 32 00:03:44,580 --> 00:03:51,130 we end up with nineteen point five three million vote step size right. 33 00:03:51,150 --> 00:03:58,170 So this order is for the short overview on a disease and we shall see how the work programmatically. 34 00:03:58,170 --> 00:03:59,670 I'll see you in the next lesson.