4011 (Quad, 2 input NAND Gates)
The 4011 is a CMOS chip with four NAND gates. Because each gate has two inputs and it has 4 gates inside, it’s usually called a Quad 2-Input NAND Gate.
A NAND gate combines the functionality of AND plus NOT gates. It gives a LOW output only when all inputs are HIGH; otherwise, the output is LOW.