# TEST2 EECS.docx - Logic Gates Gate A device that performs a...

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Logic Gates Gate A device that performs a basic operation on electrical signals - There are six types of gates: NOT, AND, NAND, OR, XOR, NOR - Logic diagrams are usually black and white, but colour can be added to improve clarity Circuits Gates combined to perform more complicated tasks Boolean Expressions Uses Boolean algebra to express two valued logic Logic Diagrams A graphical representation of a logic gate Truth Tables A table showing all possible input values and associated output values Functional Notation Uses a function name followed by a list of arguments in place of the operands used for Boolean expressions Transistor: Trans Conductance Variable Resistor It two major roles include: amplifier and binary switch NOT Gate - Accepts one input signal (0 or 1) and returns the complementary (opposite) signal as an output - Sometimes referred to as an inverter because it inverts input signals NOT Gate using a transistor
AND Gate - An AND gate accepts two input signals - If both are 1, then the output is 1; otherwise the output is zero AND Gate using transistors NAND Gate - The “NOT of AND” gate accepts two input signals - If both are one, the output is zero, otherwise the output is 1 - The opposite of AND OR Gate - If both are zero, then the output is zero; otherwise the output is 1 - If both are false, then the output is false; otherwise the output is true
OR Gate using transistors Functional Equivalents XOR Gate - Accepts only two input signals - If both are the same, then the output is zero; otherwise it is 1 XOR is called the “ exclusive OR ” because the output is the same as OR excluding the 1,1 input to get a 1 output
NOR Gate - The Not of OR gate accepts two inputs - If both are zero, then the output is 1; otherwise the output is 0 Gates with more inputs -