PROJECTS FOR YOU: ANALOG TO DIGITAL CONVERTERS

Monday, 4 February 2013

ANALOG TO DIGITAL CONVERTERS

Theory :-

As you all know that in the world of electronics all the microcontrollers and microprocessors works on DIGITAL SIGNAL, but from the sources like battery we get a ANALOG SIGNAL. So in embedded systems it is mandatory to convert the analog signal into digital signal.

So for converting the analog signal into digital signal we use operational amplifiers(OP-AMP). We use operational amplifiers as a voltage comparator . A op-amp is shown in figure below :-

We fix a voltage at negative input with the help of variable resistor of 10k ohm and at the positive input we give our analog signal. If the analog signal is grater than the fix voltage at negative input then we get 1 in output(means +5V) and if the analog signal voltage is less than the voltage at negative input then we get 0 at output(means 0V).

Note :-

Set the negative input voltage with the help of variable resistor according to your requirement.

you can see a A to D converter in below fig.

There are several OP-AMP ICs are available like :- lm358, 741, lm324 etc.
Here we use LM324 which have 4 op-amps in it.

Now we construct a A TO D converter. With the help of above circuit and pin out diagram of lm324 we construct a A TO D CONVERTER in INVERTING & NON-INVERTING mode.

Schematic :-

this is the schematic for NON-INVERTING configuration.
take the outputs from output pins. Give your analog input signal to pin 3,5,10,12.

For INVERTING configurations connect the variable resistors ant negative inputs and give give analog input at positive terminal.

THE PCB LAYOUTS ARE THE MIXED OF BOTH INVERTING AND NON INVERTING CONFIGURATION.

DOWNLOAD THIS PICTURE AND ZOOM IN SO YOU CAN SEE CLEARLY ALL COMPONENTS.

Pcb layouts :-

top/component view

bottom view

This is the layout of original size pcb. In the above layout the upper lm324 ic is configured in non-inverting mode and lower lm324 ic is configured in inverting mode.

Photos :-