voltage drop

[samina]

can anyone tell me why the voltage drop or loss occur at different logic gates
for example the input of an And gate was 3.3 v and output was 2.9, why it happened?

 

[legend killer]

Ideally the output should be 5 V.But since you are drawing some current from its output,there is
some voltage drop in the internal resistance.The more current you draw,the less voltage you get

 

[mneary]

5V is not the ideal output from 3.3V logic.

The rest of the answer is correct; the output will always be some amount less than the power supply due to resistance and other losses.

 

[audioguru]

A Cmos output goes up to the supply voltage when it drives Cmos inputs.
Old TTL outputs have base-emitter and resistor voltage drops at their output.