Transcript Lecture 1 - Rabie Ramadan

Lecture 1
Introduction to Electronics
Rabie A. Ramadan
[email protected]
http://www.rabieramadan.org/classes/2014/electronics/
Welcome Back
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Class Organization
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Attendance is very important
Assignments
Projects
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Class Rules
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I am not here to punish you
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Trust yourself and do your best

I want you to learn and compete with others
working on the same field
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I want you to be confident when you speak with
others
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Textbooks
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Class Format
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Some presentations by myself
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Q& A in class
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Quick questions in class to be answered
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Topics to be Covered next few
Lectures
• That electronic circuits process signals, and thus understanding electrical
signals is essential
• The Thevenin and Norton representations of signal sources.
• The representation of a signal as the sum of sine waves.
• The analog and digital representations of a signal.
• The most basic and pervasive signal-processing function: signal
amplification, and correspondingly, the signal amplifier.
• How amplifiers are characterized (modeled) as circuit building blocks
independent of their internal circuitry.
• How the frequency response of an amplifier is measured, and how it is
calculated, especially in the simple but common case of a single-time
constant (STC) type response.
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Introduction
• Microelectronics refers to the integrated-circuit (IC)
technology.
• Contains hundreds of millions of components in a small piece
of silicon (known as a silicon chip) whose area is on the order
of 100 mm2.
Applications
Introduction
• One such microelectronic circuit is a complete digital
computer, which accordingly is known as a microcomputer
or, more generally, a microprocessor.
• We shall study electronic devices that can be used singly (in
the design of discrete circuits) or as components of an
integrated-circuit (IC) chip.
• We shall study the design and analysis of interconnections of
these devices.
• We shall also learn about available IC chips and their
application in the design of electronic systems.
Introduction
• Today we will learn about signals and about one of
the most important signal-processing functions
electronic circuits are designed to perform, namely,
signal amplification.
Signals
• Signals contain information about things and
activities around us in the physical world.
• Information about the weather including
temperature , humidity, wind speed , etc.
• The voice of radio announcer in the
microphone is a signal.
Signals
• To extract required information from a set “signals” ,
there are some “processing” .
• Usually the processing done by “electronic
systems”.
• To do so, the signal must be first converted to
electrical signals , voltage or current.
• This conversion is done by “transducers “
Transducers
• A variety of transducers exist .
• Each type of suitable for special type of physical
signal.
• Sound wave generated by human is converted into
electrical signals using microphone .
Transducers
• We are not interested in transducers by themselves.
• We will assume that the signals are already exist in a
form of voltage or current.
Thevenin Form
• The signal is represented by Vs(t)
• Source resistance Rs
Norton Form
• The signal is represented by current
source is (t)
• Source resistance Rs
Source Resistance
• Rs in Thevenin preferred to be low
• Rs in Notron preferred to be High
Relation between the two forms
Voltage Divider Rule
Example
Example
Problem
Hint
Current Divider Rule
Example
Example
Example
Problem
Hint
Just Smile
Slide 2- 31
Thevenin –
V0 Computation at RL
• Rs is the source resistance
• RL is load resistance
• Compute the load voltage V0 ?
Thevenin –
V0 Computation at RL
Norton
Compute i0
Exercises
http://people.clarkson.edu/~jsvoboda/eta/dcWorkout/thevenin.pdf
Slide 2- 36
Signals and Time
• The signal can be represented by TimeVarying quantity as follows:
Frequency Spectrum of Signals
• An extremely useful characterization of a Signal, and for
that matter of any arbitrary function of time, IS In
terms of its frequency spectrum.
• Such a description of signals is obtained through the
mathematical tools of Fourier series and Fourier
transform.
• Suffice it to say that they provide the means for
representing a voltage signal Vs(t) or a current signal is(t)
as the sum of sine-wave signals of different frequencies
and amplitudes.
Frequency Spectrum of Signals
• This makes the sine wave a very important
signal in the analyses, design, and testing of
electronic circuits
Frequency Spectrum of Signals
Analog and Digital Signals
• Analog Signals
– Handled by analog Circuits
Analog and Digital Signals
• Digital Signals:
– Signals are represented in a form of numbers
– Each number represents a signal magnitude at an
instance of time.
From Analog to Digital
• Sampling
From Analog to Digital
• The signal is no longer continuous like in its analog form
• It is said Io be quantized discretized or digitized
Important Note
Important Note
Important Note
• If we use N binary digits (bits) to represent each
sample of the analog signal. then the digitized sample
value can be expressed as
• b0 is the Least Significant Bit (LSB)
• bN-1 is the Most Significant Bit (MSB)
Analog todigital converter ( A/D or ADC)
• increasing the number of bits reduces the quantization error
and increases the resolution of the analog-to-digital
conversion.
• however, usually mobtained at the expense of more complex
and hence more costly circuit implementations
Exercise