Learning Guide Unit 2/3

Question 1

What is N-Type Silicon ‘doped’ with?

Answer 1

Arsenic, Phosphorus, Antimony

Question 2

What is P-Type Silicon ‘doped’ with?
BGA

Answer 2

Boron, Gallium, Aluminum

Question 3

2’s Complement is also known as?

Answer 3

Radix complement

Question 4

What is -8 in 2’s Complement?

Answer 4

1000

Question 5

What is the 2’s complement of 0001?

Answer 5

1111 = -1

Question 6

A special-purpose chip designed to add 1 to a given number.

Answer 6

Incrementer

Question 7

This chip was designed to add three bits.

Answer 7

Full-Adder

Question 8

A “ “ consists of logic gates whose outputs, at any time, are determined by combining the values of the inputs.

Answer 8

Combinational Circuit
Source: Taipala, D. (2013, June 6). CS1104 computer systems unit 3 lecture 1

Question 9

For n input variables, there are “ “ possible binary input combinations.

Answer 9

2n
Source: Taipala, D. (2013, June 6). CS1104 computer systems unit 3 lecture 1

Question 10

How many possible outputs are there for each binary combination of the input variables?

Answer 10

One.
Source: Taipala, D. (2013, June 6). CS1104 computer systems unit 3 lecture 1

Question 11

A combinational Circuit can be described by? Hint: 2 answers

Answer 11

1. A truth table that lists the output values for each combination of the input variables, or
2. m Boolean functions, one for each output variable

Source: Taipala, D. (2013, June 6). CS1104 computer systems unit 3 lecture 1

Question 12

Combinational circuits are “ “. Thus, the output value depends ONLY on the current input values.

Answer 12

Memory-less.
Source: Taipala, D. (2013, June 6). CS1104 computer systems unit 3 lecture 1

Question 13

What two things do sequential circuits consist of?
Hint: how do they remember?

Answer 13

Combinational logic as well as memory elements (used to store certain circuit states). Outputs depend on BOTH current input values and previous input values (kept in the storage elements).
Source: Taipala, D. (2013, June 6). CS1104 computer systems unit 3 lecture 1

Question 14

What type of decoder is this? For each possible input combination, there are seven outputs that are equal to 0 and only one that is equal to 1.

Answer 14

3-to-8 Line Decoder.

Source: Taipala, D. (2013, June 6). CS1104 computer systems unit 3 lecture 1

Question 15

The decoder is also used in conjunction with other code converters such as a “ “ decoder.

Answer 15

BCD-to-seven_segment decoder.
Source:
Taipala, D. (2013, June 6). CS1104 computer systems unit 3 lecture 1

Question 16

A decoder with an enable input is referred to as a?

Answer 16

Decoder/Demultiplexer
Source: Taipala, D. (2013, June 6). CS1104 computer systems unit 3 lecture 1

Question 17

This device uses a set of control inputs to select which of several data inputs is to be connected to a single data output.

Answer 17

A multiplexer

Question 18

The simplest output from a digital circuit is an?

Answer 18

LED (Light-Emitting Diode)

Question 19

What circumstances would cause an LED to not light up? Hint: 3 potential answers.

Answer 19

1. If there is no current
2. If the current tries to flow in the opposite direction
   2a. You may also have the LED turned around.

Question 20

How do you reduce the current to an LED?

Answer 20

With a resistor.

Question 21

Selects or enables a specific device or it routes data to the appropriate subsystem.

Answer 21

Scheme

Question 22

What is an Active-Low Operation?

Answer 22

Using Logic 0 to enable devices and a logic 1 to disable them.

Question 23

What is the special notation that is used to indicate an active-low signal?

Answer 23

The signal input has a bar over it or sometimes the line that is drawn into or out of the system diagram will also pass through an inverter circle to identify the signal as active-low.

Question 24

The simplest input to a digital circuit is a?

Answer 24

switch

Question 25

What is a pull-up resistor?

Answer 25

A pull-up resistor protects the integrated circuit by limiting the current flow while still providing a positive voltage that can be read as a logic one.