Transcript Digital electronics

Basic Electronics
Kashif Bashir
Email:[email protected]
Web:http://www.Taleem.greatnow.com
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Course Books!!
Text Books:
 Basic Electronics (Eightth Edition)
By Bernard Grob
Electronics Devices (Fifth edition)
By Thomas L. Floyd
Reference Book:
 Introductory Electronic Devices And circuits
By Robert T Paynter.
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Marks Distribution!!
10% Project
10% Quizzes
5% Assignment
30% Hourly
40% Final Term
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Course Description
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Survey of Electronics
Int. to Basic Electronics
Ohm’s Law
Series Circuits
Parallel Circuits
Series-Parallel circuits
Voltage Dividers and
Current Dividers
 Kirchhoff’s Laws
 Alternating Voltage and
Current
 Capacitance
 Int. to Semiconductors
 Diode Application
 Bipolar Junction Transistors
 Digital Electronics
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Introduction
• The name electronics comes form the electron, which is
a very small, invisible particle of electricity present in all
materials.
• The fields of electronics name some main divisions.
• Every type of electronic equipment makes use of solidstate semiconductor devices. The main factor in their
operation is the ability to control the flow of electrons to
obtain the desired elects.
• An integrated circuit (IC) chip contains many transistors
and diodes in one very small package.
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Wireless Broadcasting
 Broadcasting means to send out in all directions. The
transmitter sends out electromagnetic radio waves
radiated from its antenna.
 Receivers can pick up the transmitted radio signal by
means of a receiving antenna or aerial. The receiver
reproduces the desired signal transmitted by the
broadcast station.
 There are many radio signals in space from different
transmitters, but the receiver can be tuned to the
frequency of the station we want.
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Radio broadcasting b/w transmitter and receiver. An
amplitude modulating (AM) carrier wave shown here
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Radio Broadcast Services
• Radio is an abbreviated form of radiotelegraph and
radiotelephone. The word radio means radiation for
wireless transmission. At first, communication was by
radiotelegraph, using short dots and longer dashes in the
Morse code.
• The transmission distance for wireless communication
can be less then a mile or as much as 5000miles,
depending on the type of services
• All radio services in the United states are regulated by the
Federal Communications Commission (FCC). The FCC
assigns the RF(radio frequency) carrier frequencies for
transmission and monitors use of the airwaves.
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Radio Applications
• Standard AM Radio Broadcast Band. Amplitude
modulation is used in transmission of the assigned RF
carrier wave. Stations are assigned every 10 kHz in the
band of 540 to 1700 kHz.
• FM Radio Broadcast Band. This band is 88 to 108 MHz,
with stations assigned every 200 kHz or 0.2 MHz.
• Television Broadcasting. Television is just another
application of wireless radio communications, but with
picture information in addition to the sound signal. Two
separate carrier waves are transmitted by the station in its
assigned channel. One carrier is an AM picture signal,
modulated by a video with the picture information.
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Note:
The total bandwidth required for AM
can be determined from the bandwidth
of the audio signal:
BWt = 2 x BWm.
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Figure 5-41
Amplitude Modulation
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Figure 5-43
AM Band Allocation
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Example
We have an audio signal with a bandwidth of 4 KHz.
What is the bandwidth needed if we modulate the signal
using AM? Ignore FCC regulations.
Solution
An AM signal requires twice the bandwidth of the
original signal:
BW = 2 x 4 KHz = 8 KHz
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Note:
The total bandwidth required for FM
can be determined from the bandwidth
of the audio signal:
BWt = 10 x BWm.
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Figure 5-44
Frequency Modulation
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Figure 5-46
FM Band Allocation
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Example
We have an audio signal with a bandwidth of 4
MHz. What is the bandwidth needed if we modulate
the signal using FM? Ignore FCC regulations.
Solution
An FM signal requires 10 times the bandwidth of
the original signal:
BW = 10 x 4 MHz = 40 MHz
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 The other carrier is an FM sound signal modulated by
the audio signal.A television channel is 6 MHz wide to
include both the picture and sound signals for each
broadcast station. Channel 2, for instance, is 54 to 60
MHz.
 Amateur Radio. This field is one of the largest
noncommercial radio services. Amateur radio operators,
or “hams” usually build and operate their own
transmitters and receivers to call one another in one of
the assigned bands. A popular band 7 to 7.3 MHz.
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Application of Electronics
Three logical groupings of electronics applications are
defined here.
1. Communications electronics. This field includes AM
radio, FM radio with stereo, television with color. The
equipment is divided between transmitters and
receivers.
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Satellite communications is also a transmit-receive
system using electromagnetic radio waves. The satellite
just happens to be orbiting around the earth at a height
of about 22.300 miles in order to maintain a stationary
position relative to the earth.
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Geosynchronous Orbit
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2. Electric Power. These applications are in the generation
and distribution of 60-Hz ac power, as the source of
energy for electrical equipment. Included are lighting,
heating, motors, and generators.
3. Digital electronics. The circuits for digital applications
operate with pulses of voltage or current. A pulse
waveform is either completely ON or OFF because of
the sudden changes in amplitude. In-between values
have no function.
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Electronic Components
1. Semiconductors.
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Diode rectifiers
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transistor amplifiers (either as separate, discrete
components or as part of an IC chip.
2. Electron tubes: vacuum-tube diodes, amplifiers, and the
cathode-ray tube (CRT) for a visual display device. A
glass envelope en-closes the required electrodes in a
vacuum.
3. Visual display devices. CRT , solid-state types of
displays (light-emitting diode (LED) and liquid-crystal
display (LCD)).
4. Resistors. 5. CapacitorsKashif
or Bashir
condensers. 6. Inductors or
coils.
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Digital Logic Gates
One of the most common types of digital circuits is the logic
gate. Its function is to allow only certain combinations of
input pulses to activate the circuit. Logic gates are used in
just about all-digital applications such as calculators,
computers, and clocks, to name just a few.
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