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Foundations of Technology
Basic Circuits
Teacher Resource – Unit 4 Lesson 4
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STEMCenter for Teaching and Learning™
Foundations of Technology
The BIG Idea
Big Idea:
Troubleshooting allows users to continue to
use and maintain the proper operation of a
system or product.
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STEMCenter for Teaching and Learning™
Foundations of Technology
Basic Circuits
All electronic circuits have a path for
electrons to flow and an energy source.
Electrons will flow from the
negative(-) to the positive(+).
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The amount of electron flow
will depend on resistance.
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STEMCenter for Teaching and Learning™
Foundations of Technology
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Direct Current
Direct Current (DC) electrons flow in only
one direction.
Examples: a battery, hand held electronics
such as an iPod and other devices like an
automobile
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STEMCenter for Teaching and Learning™
Foundations of Technology
Alternating Current
Alternating Current (AC) electrons flow
back and forth, negative (-) to positive (+)
to negative (-)
Examples: the electrical appliances at your
house
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STEMCenter for Teaching and Learning™
Foundations of Technology
The Atom
All matter is made of atoms.
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The atom is made of
three things:
Protons
Neutrons
Electrons
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STEMCenter for Teaching and Learning™
Foundations of Technology
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Electrons
Electrons rotate around the group of
proton and neutrons.
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When electrons
move from one atom
to the next, it is
called electron flow.
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STEMCenter for Teaching and Learning™
Foundations of Technology
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Electrons
Opposite electrical charges
always attract and
like electrical charges
always repel.
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Balanced atoms normally
have an equal number
of electrons and protons,
which means they are
electrically neutral.
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STEMCenter for Teaching and Learning™
Foundations of Technology
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Ions
Ion particles occur when an atom loses or
gains an electron causing an imbalance.
When an imbalance
occurs, Ion's will take or
release an electron to
become balanced again,
causing electron flow.
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STEMCenter for Teaching and Learning™
Foundations of Technology
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Ions
Ion’s can be charged:
Positive (+), which has one less
electron than proton.
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Negative (-), which has
one more electron than
proton.
The positive Ion attracts
to a negative Ion to
become balanced.
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STEMCenter for Teaching and Learning™
Foundations of Technology
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Electron Orbits
Electrons rotate around the atom at
different orbits.
Bound electrons orbit
around the nucleus
on the inner rings
Free electrons are
loosely held and orbit
around the outermost
ring which is known as
the valance ring
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STEMCenter for Teaching and Learning™
Foundations of Technology
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Insulators
An insulator is any material that prevents
the flow of electrons.
Insulators typically have
five to eight free electrons
in the outer ring, which
means they are tightly
held to the atom and
cannot easily move.
Insulator material includes
glass, rubber and plastic.
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STEMCenter for Teaching and Learning™
Foundations of Technology
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Conductors
A conductor is any material that easily
allows electrons to flow.
Conductors typically have
one to three free electrons
in the outer ring, which
means they are loosely
held to the atom and can
easily move.
Conductor material
includes copper and gold.
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STEMCenter for Teaching and Learning™
Foundations of Technology
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Semiconductors
A semiconductor is neither a good
conductor or insulator.
Semiconductors have
exactly four free electrons in
the outer orbit and are
commonly used to
manufacture diodes,
transistors, and integrated
circuit chips.
Semiconductor material includes
carbon, silicon, and germanium.
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STEMCenter for Teaching and Learning™
Foundations of Technology
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Ohm’s Law
Proposed by George Ohm, and is the
relationship between Voltage, Current and
Resistance.
Ohm suggested that if you double
the Voltage across something
V
that provides resistance, then
the current would double.
+
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Voltage (V) = Current (I) X Resistance (R)
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STEMCenter for Teaching and Learning™
Foundations of Technology
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Voltage
Voltage is the electrical force that moves
electrons through a conductor.
Voltage is electrical pressure that pushes
electrons.
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STEMCenter for Teaching and Learning™
Foundations of Technology
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Current
Current is the quantity or flow rate of
electrons moving past a point.
Current flow is also known as amperage,
or amps for short.
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I
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STEMCenter for Teaching and Learning™
Foundations of Technology
R
Resistance
Resistance is the force that reduces or
stops the flow of electrons and opposes
voltage.
V
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STEMCenter for Teaching and Learning™
Foundations of Technology
R
Resistors in Series
In a Series circuit, the current through two
or more resistors is the same, and the
circuit is connected in a series.
The total resistance of
the collection is the sum
of the individual
resistances.
In series, electrons have only one path to
follow to complete the circuit and must travel
through all components.
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STEMCenter for Teaching and Learning™
Foundations of Technology
Resistors in Parallel
In a Parallel circuit, the voltage through
two or more resistors is the same, and the
circuit is connected in parallel.
The total resistance of the
collection is divided among
the three resistors .
In parallel, electrons have
multiple paths to follow to
complete the circuit and do not need to travel
through all components in the circuit to do so.
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STEMCenter for Teaching and Learning™
Foundations of Technology
Parts of the Electronics Kit
2 Battery
Snaps
15
Wires
Potentiometer
Solderless Breadboard
Diode
Spea
ker
Battery
Transist
ors
Photocell
SCR
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Foundations of Technology
3
LED’s
555 Timer
Push Button
Capacitors
Parts of the Electronics Kit
LED
Resistor
Diode
Photocell
3904 Transistor
Speaker
3906 Transistor Push Button
“Can” Capacitor Potentiometer
Ceramic Disc Capacitor
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Foundations of Technology
Battery
SCR
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STEMCenter for Teaching and Learning™
Foundations of Technology
470K ohm (Yellow, Violet, Yellow, Gold)
120K ohm (Brown, Red, Yellow, Gold)
2 @ 33K ohm (Orange, Orange,
Orange, Gold)
3 @ 10K ohm
(Brown, Black,
Orange, Gold)
16K ohm (Brown, Blue, Orange, Gold)
3.3K ohm (Orange, Orange, Red, Gold)
2.2K ohm (Red, Red, Red, Gold)
4 @ 1K ohm (Brown, Black, Red, Gold)
470 ohm (Yellow, Violet, Brown, Gold)
3 @ 330 ohm (Orange, Orange
Brown, Gold)
3 @ 220 ohm (Red, Red, Brown, Gold)
2 @ 100 ohm (Brown, Black,
Brown, Gold)
2 @ 47 ohm (Yellow, Violet,
Black, Gold)
10 ohm (Brown, Black, Black, Gold)
Parts of the Electronics Kit
Color Codes
Resistors have four (4) color bands on them
called the “color code”
Band 1 = 1st Digit
Band 2 = 2nd Digit
Band 3 = Multiplier.
Band 4 = Tolerance
Gold = 5%
Silver = 10%
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STEMCenter for Teaching and Learning™
Foundations of Technology
Building a Circuit
The Breadboard includes two sides
(a-e and f-j) and the “ditch”
or the space in the middle.
The holes are connected by
rows not columns.
© 2013 International Technology and Engineering Educators Association,
STEMCenter for Teaching and Learning™
Foundations of Technology
Practice Building a Circuit
Build the circuit below:
9
Volts
+
-
R = 1000 Ohms
I
1000 ohms resistor
(brown, black, red, gold)
© 2013 International Technology and Engineering Educators Association,
STEMCenter for Teaching and Learning™
Foundations of Technology
Practice Building a Circuit
Use your simple circuit and measure for
Volts, Current and Resistance.
Place the digital
multimeter in
series to measure
current.
9
Volts
Use the
multimeter to
measure
voltage
+
-
R
I
Use the
multimeter to
measure the
resistance.
1000 ohms resistor (brown, black, red, gold)
© 2013 International Technology and Engineering Educators Association,
STEMCenter for Teaching and Learning™
Foundations of Technology
Practice Building a Circuit
Do the math using Ohm’s Law to find the actual
value of the resistor - What does it measure?
Place the digital
multimeter in
series to measure
current.
9
Volts
Use the
multimeter to
measure
voltage
+
-
R
I
Use the
multimeter to
measure the
resistance.
1000 ohms resistor (brown, black, red, gold)
© 2013 International Technology and Engineering Educators Association,
STEMCenter for Teaching and Learning™
Foundations of Technology