Untitled Quiz

Course Information

• Course Name: Basics of Electrical and Electronics Engineering
• Course Code: 24U0104
• Class: FE (Engineering Sciences) (Common for all branches)
• Unit No. 2: Digital Electronics

Unit 2: Digital Electronics – Contents

• Logic gates
• Flip-Flops
• Shift registers and synchronous counters
• Analog to Digital and Digital to Analog converters (ADC/DAC)
• Recording and playback concepts
• Digital audio and video formats
• Concepts of Microprocessor, Microcontroller

Prerequisites

• Signals can be of two types: analog and digital.
• Analog signals have continuous values and can have an infinite number of values.
• Digital signals have a finite number of distinct values, and are discrete signals.
• Logic levels represent states: High (1) corresponds to a higher voltage (e.g., 5V, 3.3V), and Low (0) to a lower voltage (e.g., 0V).

Logic Gates

• Fundamental building blocks of digital circuits.
• Perform basic logical functions.
• Each gate takes one or more binary inputs (0 or 1) and produces a single binary output based on a logical operation.
• Various types: AND, OR, NOT, NAND, NOR, XOR, XNOR.

AND Gate

• Has two or more inputs and one output.
• Output is high (1) only when all inputs are high.
• Output is low (0) if any of the inputs are low.

OR Gate

• Has two or more inputs and one output.
• Output is high (1) if any or all inputs are high.
• Output is low (0) only when all inputs are low.

NOT Gate

• Single input, single output.
• Known as an inverter.
• Inverts the binary signal at the input.

Universal Gates

• NAND and NOR gates are called "universal gates"
• Allow creation of any other logic gate.
• Allow for the creation of complete circuits.

NAND Gate

• Has two or more inputs and one output.
• Output is low (0) only when all inputs are high.
• Output is high (1) in all other cases.

NOR Gate

• Has two or more inputs and one output.
• Output is high (1) only when all inputs are low.
• Output is low (0) in all other cases.

Exclusive-OR (EX-OR) Gate

• Has two or more inputs and one output.
• Output is high (1) when an odd number of inputs are high
• Output is low (0) when both inputs are low or both are high.

Exclusive-NOR (EX-NOR) Gate

• Has two or more inputs and one output.
• Output is high (1) when the inputs have the same value (both high or both low).
• Output is low (0) when the inputs have different values.

Summary of Gates

• AND Gate: Outputs 1 only if all inputs are 1.
• OR Gate: Outputs 1 if at least one input is 1.
• NOT Gate: Inverts the input.
• NAND Gate: Outputs 0 only if all inputs are 1.
• NOR Gate: Outputs 1 only if all inputs are 0.
• XOR Gate: Outputs 1 if an odd number of inputs are 1.
• XNOR Gate: Outputs 1 if all inputs are the same.

Categories of Logic Circuits

• Combinational Circuits: Output depends only on current input values.
• Sequential Circuits: Output depends on current input values and previous circuit states

1-bit Memory Cell

• Fundamental building block for digital memory.
• Stores a single binary digit (0 or 1).
• Implemented using various configurations of flip-flops.
• Can be implemented using SR Latch.

SR Latch

• Basic memory circuit.
• Made from cross-coupled NOR or NAND gates.
• Stores a single bit of information.
• Has two inputs: Set (S) and Reset (R).

Clock

• In digital electronics, signals are used with rectangular waveforms.
• Logic 1 represents an electric pulse.
• Logic 0 represents the absence of an electric pulse.

Flip-Flop

• Electronic logic circuit with two inputs and one output.
• Used for storing data values permanently until changed.
• Basic technology behind computer memory chips.

S-R Flip-Flop

• Output changes only when the timing control is high.
• Timing control (gate, clock, latch enable) coordinates when new data is written.
• Holds data while the clock is low.

D Flip-Flop

• Variant of S-R flip-flop.
• Eliminates the problem of undefined outputs (S=R=1).
• Output follows the D input while the clock is high.
• Holds the last value of Q when the clock is low.

J-K Flip-Flop

• Versatile flip-flop.
• No indeterminate condition in operation.
• Output changes its previous condition when all inputs are 1 and clock is applied.

Toggle (T) Flip-Flop

• Single-input version of the J-K flip-flop.
• Output toggles (changes) with each clock pulse.
• Outputs remain in hold state (no change) when the clock is low.

Shift Registers

• Sequential circuits for storing and shifting data.
• Constructed from multiple flip-flops.
• Increase storage capacity by connecting flip-flops in a chain.
• Data can be shifted left or right.
• Various modes of operation (SISO, SIPO, PISO, PIPO).

Counters

• Sequential circuits for counting input pulses.
• Asynchronous (ripple) counters: Each flip-flop toggles based on the output of the preceding flip-flop.
• Synchronous counters: All flip-flops change state simultaneously based on a common clock signal.

ADC and DAC Converters

• Convert analog signals to digital signals (ADC) or vice versa (DAC).
• Necessary to convert physical quantities to digital form for easier processing and storage.

Digital Audio Formats

• MP3 (MPEG Audio Layer III)
• WAV (Waveform Audio File Format)
• FLAC (Free Lossless Audio Codec)
• AAC (Advanced Audio Codec)
• OGG (Ogg Vorbis)

Digital Video Formats

• MP4 (MPEG-4 part 14)
• AVI (Audio Video Interleave)
• MOV (QuickTime Movie)
• MKV (Matroska Video)
• WMV (Windows Media Video)

Microprocessor

• Integrated circuit (IC) containing the core functions of a CPU.
• Programmable.
• Accepts binary data as input, processes it as per instructions in memory.
• Produces output.
• Used in personal computers.

Microcontroller

• Includes CPU, memory, and I/O functions on a single chip.
• More cost-effective and less complex than using separate components.
• Used in embedded systems.

Applications of Flip-Flops

• Memory storage
• Clock control
• Data synchronization