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WHAT'S YOUR ENGINEERING QUOTIENT?

Problem 4—Draw the schematic of a 2-input CMOS NAND gate and explain its working.

Its working can be explained as follows:

• If A is low, Q1 is on and Q2 is off. The output is high, regardless of the state of B.
• If B is low, Q4 is on and Q3 is off. The output is high, regardless of the state of A.
• If A and B are both high, then Q1 and Q4 are both off and Q2 and Q3 are both on. The output is low.

This can be summarised by the following truth table:

A	B	X
0	0	1
0	1	1
1	0	1
1	1	0

Contributor: Naveen PN

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