# 08 - Definitions, Logic and key concepts

1. Boolean logic is about storing numbers in OR, AND and NOT gates.
```Your definitions need to be perfect and accurate.
What is Boolean Logic?```

True

False

2. What is the difference between a gate and a circuit?
```Gate and a circuit
==================
#1 >> A gate accepts one or more input signals and produces an output signal.

#2 >> Each type of gate performs one logical function.

#3 >> A circuit is a combination of gates designed to accomplish a more complex logical function.

#4 >> A gate and a circuit are the same thing

#5 >> Each type of gate can perform multiple (up to 128 million) logical functions.```

3,4,5

1 only

1,2,3

2,3,4

3. What are the three notational methods for describing the behavior of gates and circuits?

CPUs, Computers and Chips

Voltage, Current and Binary input

Gates, circuits and transistors

Boolean expressions, logic diagrams, and truth tables

4. Fill in the blanks: Logic diagrams use a graphical representation to describe the behavior of __________________________

gates and circuits

Voltage and Current

CPUs and Chips

RAM and ROM

5. Fill in the blanks: Truth tables define the behavior of gates and circuits by showing all _______________________

possible combinations of binary sequences

binary inputs

voltage currents

possible input and output combinations of the gates and circuits.

6. True or False: A gate can accept one or more input signals, but can produce only a single output value.`

TRUE

FALSE

7. Which of the following is NOT a gate:
`NOT, AND, FOR, OR, XOR, NAN, NOR`

NAN

XOR

NOT

FOR

8. For the boolean expression: : X = NOT A what is the input and what is the output?

A and X are both input signals only

A and X are both the input and the output

A is the input signal and X is the output

A is the output signal and X is the input

9. What type of gate takes a binary input value and inverts it.

XOR

NOT

AND

OR

10. What is used in a gate to establish how the input values map to the output value?

A gate

A voltage signal

A transistor

A binary bit

11. What does this describe?
`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.`

The behaviour of a transistor

The behaviour of logic gates

The behaviour of the CPU

The behaviour of bit patterns

12. 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

FALSE

TRUE

13. If an electric 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 ______volts.

3

0

1

2

14. An AND gate and an OR gate both require two transistors. What about a NOT gate?

2

3

1

4

15. What is the boolean expression for a three-input OR gate

X = ABC

A . B . C = X

X = A . B . C

X = A + B + C