Welcome back.
In this lesson we shall give an overview of what an ADC or an analog to digital converter is analog
to digital converters are among the most widely used devices for data acquisition digital computers
use binary or discrete values.
But in the physical world everything is analog or continuous temperature pressure humidity velocity
are just a few examples of physical quantities that we deal with every day.
A physical quantity is converted to electrical signals using a device called transducer and a transducer
simply converts a physical quantity to Edo voltage or current transducers used to generate electrical
output are referred to us same source same source for temperatures velocity pressure light and many
other natural physical quantities.
Produce an output that is voltage or sometimes current.
Therefore we need an analog to digital converter to translate the analog signals to digital numbers
so that the microcontroller can read and process these numbers.
Now let's talk about the concept of HD you resolution and ATC has in bit resolution where end can be
eight ten twelve sixteen or even twenty four so you hear.
So you hear of people saying this HD is 10 bit as twelve bit as sixteen bit higher resolution HD provide
a smaller step size where step size is the smallest change that can be detected by an ADC this table
over here shows the number of steps as well as the step size given the number of bits the ABC has so
for instance an AIDS bit ADC would have 256 steps and how do we know this.
We simply do two to the power eight and we get 256 and to compute the step size we've got to take the
reference voltage into account to assume assuming the reference voltage is fivefold we simply do five
divided by 256 and this gives us nineteen and this gives us nineteen point five three million old at
ten but ADC has 1024 step size and the smallest change this 10 bit adc can detect as four point eighty
eight million old in the same way at 12 but ADC has four thousand and ninety six number of steps and
a smallest change this adc can detect is a change in one point two million votes a sixteen bit ADC would
have sixty five thousand five hundred and fifty six steps and the smallest change this ADC will be able
to detect will be zero point zero seven six million vote v ref is an input voltage use for the reference
voltage devoted connected to this pin most microcontrollers have the fear of bean and we can connect
our own input for two or we can just say use the same voltage as the one used by the MCU so the voltage
connected to the V ref been along with the resolution of the ADC chip determine the step size as you
can see over here so assume in our view ref is 5 vote and the resolution of the IT ADC is 8 bit then
we end up with nineteen point five three million vote step size right.
So this order is for the short overview on a disease and we shall see how the work programmatically.
I'll see you in the next lesson.