The basic building blocks of a DAC are:-

i) A resistive n/w, digital controlled electronic switches, a voltage ref, and I to V converter is a digital i/p code is applied to the resistance n/w the digitally controlled switches.

ii)The digitally controlled swithces are turned on or off by the digital i/p bits(o's and 1's)

iii) The o/p of the resistive n/w is in the form of current. IT can be converted into the proportional voltage with the help of the current to voltage converter.

Depending on the type of resistive n/w used, we have different types of A to D converter lets

. Binary weighted resistor DAC

. R-2R ladder type DAC.