Chapter 4 Computer Science

What is the output value of an OR gate when both inputs are 1?

1

what is a transistor made of?

a semiconductor material

circuits used for memory are what type of circuits?

memory circuits are sequential circuits because they are dependent on the existing state of the circuit as well as input to the circuit

how many digits does an S-R latch store?

one binary digit

What does the NOR operation do?

only produces a true if all inputs are false

What does the NAND operation do?

only produces false if all inputs are true

What does the XOR operation do?

produces a 0 only if all inputs are 0, and a 1 only if all inputs are 1

What does the AND operation do?

produces a 1 only if all its inputs are 1

What does the OR operation do?

produces a 1 only if one of the inputs is 1

what is the boolean expression for the NAND gate?

same as AND, but with a line over the top

what is the boolean expression for the NOR gate?

same as OR, but with a line over the top

what are sequential circuits?

circuits in which the output is a function of input values and the current state of the circuit

what is SSI (small scale integration)?

contains 1 to 10 gates

what MSI (medium scale integration)?

contains 10 to 100 gates

what is LSI (large scale integration)?

contains 100 to 100,000 gates

what is VLSI (very large scale integration)?

contains more than 100,000 gates

what are truth tables in terms of gates and circuits?

define the behavior of gates and circuits by showing all possible input and output combinations of the gates and circuits

how many output signals can a gate produce?

a gate can only produce one output value

Can a gate be designed to accept more than 2 inputs?

yes

What is the compliment property?

(A AND (A') = 0) (A OR (A') = 1)

what is the identity property?

(A AND 1 = A; A OR 0 = A)

What is Demorgan's Law?

(A AND B)' = A' OR B' (A OR B)' = A' AND B'

How can the XOR operation be expressed using other operators?

(A OR B) AND (NOT (A AND B))

How many transistors does it take for the NOT gate?

1

What is the output value of an OR gate when one value is 1 and the other is 0?

1

what is the output of an AND gate when both inputs are 1?

1

What are the three notational methods for desribing the behavior of gates and circuits?

1) Boolean expressions 2) Logic diagrams 3) Truth tables

What are the six types of gates?

1) NOT 2) AND 3) OR 4) NAND 5) NOR 6) XOR

What are the two general categories of circuits?

1) combinational circuits 2) sequential circuits

What are the six properties of boolean algebra?

1) commutative 2) associative 3) distributive 4) identity 5) compliment 6)DeMorgan's Law

What are the three terminals in a transistor?

1) source 2) base 3) ground (emitter)

How many transistors does it take for the AND gate?

2

How many transistors does it take for the XOR gate?

8

what are pins used for?

8 are used for inputs to gates, four for outputs from the gates, one for ground, and one for power

How many transistors does it take for the NOR gate?

How many transistors does it take for the OR gate?

what is the reationship between the NAND and the AND gate?

The 2 outputs are inverses of one another

What is the boolean expression for the XOR gate?

X = A (circle with the plus sign) B

what is the boolean expression for an AND gate?

X = A * B

What is the boolean expression for an OR gate?

X = A + B

what is the boolean expression for the NOT gate?

X = A'

what is a full adder?

a circuit that computers the sum of 2 bits, taking into account the carry bit

what is a half adder?

a circuit that computes the sum of two bits and produces the appropriate carry bit

What is a multiplexer?

a circuit that uses input control signals to determine which of several date input lines is to be routed to the output

how many input signals can a gate receive?

a gate can accept one or more input signals

what is used in a gate to establish how the input values map to the output value?

a transistor

what is a base in terms of a transistor?

a value that regulates a gate that determines whether the connection between the source and the ground is made

how is voltage level used to distinguish between binary digits?

a voltage level in the range of 0 to 2 volts is is interpreted as binary 0. A voltage level in the range of 3 to 5 volts is interpreted as a binary 1.

what is a source in terms of a transistor?

an electric signal

what is a CPU?

an integrated circuit

what is an integrated circuit or chip?

an integrated circuit or chip is a piece of silicon into which many gates have been embedded

How do the three terminals on a transistor operate?

an output line is usually connected to the source. If the base value is high, the source is grounded and the output is low (representing 0). If the base is low, the gate is closed, the source is not grounded, and the output is high (representing 1).

What are combinational circuits?

circuits in which the input values explicitly determine the output

how does a transistor behave?

depending on the voltage of an input signal, a transistor either acts as a wire that conducts electricity or as a resister that blocks the flow of electricity

logic diagrams and truth tables

equally powerful in expressing the processing of gates and circuits

how can gates be combined into circuits?

gates are combined into circuits by using the output of one gate as the input for another. Also the same input value can be used as input to two different gates

what happens when an electrical signal is grounded?

if an electrical signal is grounded, the signal flows through an alternative route to the ground where it can do no harm. When a signal is grounded it is pulled down to 0 volts.

What is Demorgan's law?

inverting the output if an AND gate is equivalent to inverting the individual signs first, then passing them through an OR gate

What does the NOT operation do?

inverts its inputs

what is a gate?

it accepts one or more input signals and produces one output signal. Each type of gate performs one logical function.

what is a circuit?

it is a combination of gates designed to accomplish a more complex logical function.

What does a full adder take into account?

the carry-in value

What are integrated circuits classified by?

the number of gates contained in them

what is the truth table for the NOT gate?

this inverts the input and spits that out for the output

What is the commutative property?

this says that addition problems may be applied the same way from right to left; (A + B) === (B + A)

what is the distributive property?

this says that given three boolean values, ; (A AND (B OR C)) === (A AND B) OR (A AND C) as well as (A OR (B AND C)) === (A OR B) AND (A OR C) can also be seen as (A + (B * C)) === ((A + B) * (A * C)) (A * (B + C) === (A * B) + (A * C))

what is the associative property?

this says that given three boolean variables, the order also does not matter; (A + B) + C === A = (B + C)

what is a transistor made of?

transistors are made of semiconductor material, which is neither a good conductor of electricity nor a particularly good insulator. Transistors are usually made from silicon

what is a logic diagram in terms of gates and circuits?

use a graphical representaion to describe the behavior of gates and circuits

what is a boolean expression in terms of gates and circuits?

uses the operations of boolean algebra to describe the behavior of gates and circuits

what is circuit equivalence?

when two circuits produce the same output from the same input value combination