Engineering H192 - Computer Programming
Digital Electronics
Lab 2
Winter Quarter
Gateway Engineering Education Coalition
Lab 2
P. 1
Engineering H192 - Computer Programming
Analog Vs. Digital
Winter Quarter
Gateway Engineering Education Coalition
Lab 2
P. 2
Engineering H192 - Computer Programming
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
Winter Quarter
Gateway Engineering Education Coalition
Lab 2
P. 3
Engineering H192 - Computer Programming
The Transistor
• Basic element of
digital electronics
• Can act like a
“switch”
Winter Quarter
Gateway Engineering Education Coalition
Lab 2
P. 4
Engineering H192 - Computer Programming
Boolean Algebra
• Symbolic representation of logic statements
• Uses many basic arithmetic symbols: +, -, (), etc.
Winter Quarter
Gateway Engineering Education Coalition
Lab 2
P. 5
Engineering H192 - Computer Programming
Basic Logic Circuits: AND
Symbol
Truth Table
A
Y
B
Boolean
Equation
A
B
Y
0
0
0
0
1
0
1
0
0
1
1
1
Y = A•B
Winter Quarter
Gateway Engineering Education Coalition
Lab 2
P. 6
Engineering H192 - Computer Programming
Basic Logic Circuits: OR
Symbol
Truth Table
A
Y
B
Boolean
Equation
A
B
Y
0
0
0
0
1
1
1
0
1
1
1
1
Y = A+B
Winter Quarter
Gateway Engineering Education Coalition
Lab 2
P. 7
Engineering H192 - Computer Programming
Basic Logic Circuits: NOT
Symbol
A
Truth Table
Y
A
Y
0
1
1
0
Boolean
Equation_
Y=A
Winter Quarter
Gateway Engineering Education Coalition
Lab 2
P. 8
Engineering H192 - Computer Programming
Basic Logic Circuits: NAND
• NAND = “not AND”
• Commonly used to implement other logic circuits
Symbol
Truth Table
A
Y
B
A
B
Y
0
0
1
0
1
1
1
0
1
1
0
1
Boolean
_____
Equation
Y = (A•B)Gateway Engineering Education Coalition
Winter Quarter
Lab 2
P. 9
Engineering H192 - Computer Programming
Basic Logic Circuits: NOR
• NOR = “not OR”
Symbol
Truth Table
A
Y
B
Boolean
_____
Equation
Y = (A+B)
Winter Quarter
A
B
Y
0
0
1
0
1
0
1
0
0
1
1
0
Gateway Engineering Education Coalition
Lab 2
P. 10
Engineering H192 - Computer Programming
Integrated Circuits (Chips)
• A collection of many
transistors, resistors, and
capacitors on a single
silicon wafer
• The wafer is mounted to a
carrier for ease of use and
dissipation of heat
Notches mark pin 1 end or
pin 1 of IC
(highlighted for clarity)
Winter Quarter
Gateway Engineering Education Coalition
8
1
5
7
4
1
Lab 2
P. 11
Engineering H192 - Computer Programming
Breadboards
• The “canvas” for laying
out a circuit using discrete
components (resistors,
wires, chips, etc.)
Winter Quarter
Gateway Engineering Education Coalition
Lab 2
P. 12
Engineering H192 - Computer Programming
Breadboards (continued)
• Power and ground
terminal posts
Winter Quarter
Gateway Engineering Education Coalition
Lab 2
P. 13
Engineering H192 - Computer Programming
Breadboards (continued)
• Each small row of
holes is electrically
connected inside
the breadboard
Winter Quarter
Gateway Engineering Education Coalition
Lab 2
P. 14
Engineering H192 - Computer Programming
Breadboards (continued)
• Power bus shown in
red
• Ground bus shown
in blue
• These columns of
holes are connected
electrically
Winter Quarter
Gateway Engineering Education Coalition
Lab 2
P. 15
Engineering H192 - Computer Programming
Light Emitting Diodes (LED)
• Function depends on
orientation
• Allows current to flow only
one way
• Illuminates when current is
flowing through it
• Must have current limited
by a resistor in series
Winter Quarter
Gateway Engineering Education Coalition
Lab 2
P. 16
Engineering H192 - Computer Programming
Power MOSFETs
• Allows control of high
current DC loads by lowvoltage digital signals
• With a ‘1’ signal at the
gate, current may flow
from drain to source.
Otherwise, the path is
closed
Winter Quarter
Gateway Engineering Education Coalition
Lab 2
P. 17
Engineering H192 - Computer Programming
Laying Out the Circuit
• Chips “bridge” the gaps
• Devices in adjacent
horizontal rows are
connected
• Make sure power is turned
off until circuit is finished!
Winter Quarter
Gateway Engineering Education Coalition
Lab 2
P. 18
Engineering H192 - Computer Programming
Today’s Goals
• Build digital circuits on your breadboards and
determine their function
• Test the Mystery Circuit
• Build a circuit to operate a motor with a power
MOSFET
Winter Quarter
Gateway Engineering Education Coalition
Lab 2
P. 19