The AND gate, also called AND logic or AND operation, is a Boolean product of the conjunction between the two inputs" E1" and "E2": E1*E2. The output "A" is "1" only if both inputs are "1".
If the AND gate has three or more inputs, then logical ones must be present at all inputs for the output to be logically "1". Such logic can be thought of as a series connection of switches, with current flowing across the switches only when all switches are closed. The series connection of an AND gate with a NOT gate becomes the NAND gate. Circuit families for AND gates are the 7408 in TTL logic and 4081 in CMOS technology.