Concepts of Engineering
and Technology
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Copyright © Texas Education Agency, 2012. All rights reserved.
Basic Electricity and
Electronics
Module One
Basic Electricity
Copyright © Texas Education Agency, 2012. All rights reserved.
How to learn about Electricity and
Electronics
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Everybody plays music from a CD
We start with binary data
We end up with sound coming from a
speaker
How does this work?
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Copyright © Texas Education Agency, 2012. All rights reserved.
The process involves
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Electricity
Electronics
Digital signals
Digital logic
Sound
Light and optics
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Copyright © Texas Education Agency, 2012. All rights reserved.
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Here is what our binary data looks like:
1001000100110101 1110101000111101
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Here is what our audio signal looks like:
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How do we get from one to
another?
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A series of conversion process steps
Sound is created by something that
vibrates (moves), which creates pressure
changes in the air
We can use the pressure to make
something move (a coil or diaphram)
We can use motion to create or change
some amount of electricity
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Copyright © Texas Education Agency, 2012. All rights reserved.
This work is licensed under a Creative Commons License.
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Copyright © Texas Education Agency, 2012. All rights reserved.
Sound conversion to CD data
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The value of the voltage depends on the amount
of sound (called the amplitude)
The voltage value is converted to a number that
represents how big or small the voltage is
This number has a binary code that is unique for
each voltage value
The binary code is stored as pits and spaces on
a compact disk
We will look at binary in more detail a little later
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Copyright © Texas Education Agency, 2012. All rights reserved.
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CD audio is basically a whole bunch of
numbers that record sound levels and
changes in sound levels
The voltage values are sampled at a fixed
rate: 44,100 times per second (Hertz)
We sample and record the sound level
whether there is sound or not, resulting in a
fixed amount of data per second (1.4 million
bits of data per second)
You have to understand electricity and
electronics in order to understand how (and
why) this works
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Copyright © Texas Education Agency, 2012. All rights reserved.
Basic Electricity
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Basic electricity and electronics starts with
electrons
Electrons are one of the three fundamental
particles
All work involves movement
Electrons move to create electrical work
Electronics is the study and use of systems
that control the movement of electrons
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Electrons and Charge
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How do we make electrons move?
Electrons have a charge
Like charges repel, unlike charges attract
These forces make electrons move
+
F
-
F
+
F
+
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Where do we get charge?
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Charge is a fundamental property of
nature
Electrons and protons have a charge
Electron charge is negative
Proton charge is positive
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The Atom
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The fundamental building
block of all matter
Made of protons,
neutrons,
and electrons
The type of element is
determined by the number
of protons in the nucleus
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Copyright © Texas Education Agency, 2012. All rights reserved.
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Voltage and Charge
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Voltage is a measurement of force created
by a buildup of charge
Atoms are usually neutral because they
have the same number of protons and
electrons
Charge builds up when electrons are
separated from the atom
This separation takes work in the form of
mechanical energy or chemical energy
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Copyright © Texas Education Agency, 2012. All rights reserved.
Voltage and Current
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Voltage is the force created by a buildup
of charge
Also called a potential difference
Voltage can make electrons move
Electron movement is called current flow
Current flow does the work in an electric
circuit
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Copyright © Texas Education Agency, 2012. All rights reserved.
Common Electrical Units
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The unit of charge is the COULOMB
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The unit of voltage is the VOLT
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The symbol is V, the abbreviation is V
The unit of current is the AMP
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Charge has the symbol Q, abbreviation C
Current uses the symbol I, abbreviation A
The unit of resistance is the OHM
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Resistance has the symbol W, abbreviation R
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Think in Pairs
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Electricity is two things: Voltage and
Current
Voltage has two polarities: positive and
negative
Two types of electrical power: AC and DC
Electricity has two purposes: as an energy
source (power) and as a signal
Signals can be either analog or digital
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Electricity
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A good power source
Easy to create
Easy to control
Efficient to transmit
Easy to measure
Makes everything work – our way of life
depends on it
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Copyright © Texas Education Agency, 2012. All rights reserved.
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An electric circuit must have a
complete path from one side of a
power supply (+V) to the other (-V)
Voltage across a resistor creates
current
Voltage, current, and resistance follow
a rule known as Ohm’s Law
I =V
R
Current equals voltage divided by resistance
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A Simple Circuit
Battery
+
-
Resistor
(Load)
Current
Flow
Ground
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All of the voltage is dropped across the resistor
Current flows from negative to positive
Ground is defined as zero volts
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Copyright © Texas Education Agency, 2012. All rights reserved.
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Electricity creates an electromagnetic
wave also known as a radio signal
Travels at the speed of light through
air
Travels at nearly the speed of light
through a wire
Historically most signals were analog
and used AC principles
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More recent signals are digital and
represent coded information
Digital signals are basically DC
voltage switched on and off at a
rapid rate
The basic digital switch is a
transistor
In order to understand electronics
you must understand how transistors
work
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MP3 Audio
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Research Project: Technical details of MP3
audio.
How does MP3 audio data differ from CD
audio data?
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