TTL NAND and AND gates

Chapter 3.5 TTL NAND and AND gates

Lessons In Electric Circuits Volume IV – Digital Book
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Lessons In Electric Circuits Volume IV – Digital Book

  • 3.5. TTL NAND AND AND GATES59InputAInputBOutputA BOutput000101111InputAInputBOutputEquivalent gate circuit00Exclusive-NOR gate1As indicated by the truth table, the purpose of an Exclusive-NOR gate is to output a ”high” (1)logic level whenever both inputs are at the same logic levels (either 00 or 11).• REVIEW:• Rule for an AND gate: output is ”high” only if first input and second input are both ”high.”• Rule for an OR gate: output is ”high” if input A or input B are ”high.”• Rule for a NAND gate: output is not ”high” if both the first input and the second input are”high.”• Rule for a NOR gate: output is not ”high” if either the first input or the second input are”high.”• A Negative-AND gate behaves like a NOR gate.• A Negative-OR gate behaves like a NAND gate.• Rule for an Exclusive-OR gate: output is ”high” if the input logic levels are different.• Rule for an Exclusive-NOR gate: output is ”high” if the input logic levels are the same.3.5TTL NAND and AND gatesSuppose we altered our basic open-collector inverter circuit, adding a second input terminal just likethe first: