DIGITAL ELECTRONICS Digital Electronics, Bits, Analog, Digital, Binary, Logic Analog Waveform Digital Waveforms Example of Analog System Example of Digital System Analog Vs. Digital

1. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Affiliated Institution of G.G.S.IP.U, Delhi
DIGITAL ELECTRONICS
Paper Code :- BCA 106
KEYWORDS :
Digital Electronics, Bits, Analog, Digital, Binary,
Logic
By :-HARI MOHAN JAIN

2. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
2
Introduction
to
Digital Electronics

3. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Introduction
• Digital systems are concerned with digital signals
• Digital signals can take many forms
• Here we will concentrate on binary signals since
these are the most common form of digital signals
– can be used individually
• perhaps to represent a single binary quantity or the state of a
single switch
– can be used in combination
• to represent more complex quantities

4. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
4
Analog Waveform

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Sector – 9, Dwarka Institutional Area, New Delhi-75
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Digital Waveforms
Falling or
leading edge
(b) Negative–going pulse
HIGH
Rising or
trailing edge
LOW
(a) Positive–going pulse
HIGH
Rising or
leading edge
Falling or
trailing edge
LOW
t0
t1
t0
t1

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Sector – 9, Dwarka Institutional Area, New Delhi-75
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Example of Analog System
A public address system, used to amplify sound so that it can
be heard by large audience, is one example of an application
of analog electronics.

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Sector – 9, Dwarka Institutional Area, New Delhi-75
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Example of Digital System
• A computer system is one example of an application of
digital electronics.

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Sector – 9, Dwarka Institutional Area, New Delhi-75
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Analog Vs. Digital
• Analog
– Continuous
– Can take on any values in a given range
– Very susceptible to noise
• Digital
– Discrete
– Can only take on certain values in a given range
– Can be less susceptible to noise

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Sector – 9, Dwarka Institutional Area, New Delhi-75
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Advantages Over Analog
• Programmability
• Predictable accuracy
• Maintainability
• Processed more efficiently and reliably
• Compact storage
• Does not affected by noise as well as analog
values

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Sector – 9, Dwarka Institutional Area, New Delhi-75
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Digital Electronics
• Digital electronics devices store and
process bits electronically.
– A bit represents data using 1’s and 0’s
– Eight bits is a byte – the standard grouping in
digital electronics
– Digitization is the process of transforming
information into 1’s and 0’s

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Sector – 9, Dwarka Institutional Area, New Delhi-75
11
Binary Digits
• The two digits in the binary system, 1 and 0, are called bits,
which is a contraction of the words binary digit.

12. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
How to represent 0 and 1?
• In digital circuits, two different voltage
levels are used to represent the two bits.
• The higher/lower voltage level is referred
to as a HIGH/LOW, or H/L.
12

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Sector – 9, Dwarka Institutional Area, New Delhi-75
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Logic Levels
• The voltages used to represent a 1 and a 0 are called logic
levels.
• HIGH can be any voltage between a specified minimum
value and a specified maximum value.
• LOW can be any voltage between a specified minimum
and a specified maximum.

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Sector – 9, Dwarka Institutional Area, New Delhi-75
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Positive Logic System
• A 1 is represented by HIGH and a 0 is represented by LOW.
• Also called ACTIVE HIGH LOGIC

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Sector – 9, Dwarka Institutional Area, New Delhi-75
15
Negative Logic System
• A 0 is represented by HIGH and a 1 is represented by LOW.
• Also called ACTIVE LOW LOGIC