Introduction to Engineering
Lab 4 – 1
Basic Data Systems & Circuit Prototyping
Agenda
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REVIEW OF LAB 3 RESULTS
DEFINE a DATA SYSTEM
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MAJOR TYPES
ELEMENTS
BUILD and USE TWO ELECTRICAL CIRCUITS
LAB 3 REVIEW
EFFECT OF ADDING A RESISTOR IN
PARALLEL WITH ORIGINAL
BRIGHTNESS OF LED
VOLTAGE ACROSS LED
EFFECT OF ADDING A CAPACITOR
CIRCUIT ‘RC’ TIME RESPONSE
LAB 3 REVIEW
ADDING A RESISTOR IN PARALLEL
EFFECTIVE RESISTANCE is HALVED
CURRENT is NOMINALLY DOUBLED (If V
is constant), REF. OHM’S LAW V=IR
CURRENT THROUGH THE LED is
NOMINALLY DOUBLED…ITS LIGHT
INTENSITY INCREASES.
LIGHT INTENSITY FROM THE LED is
PROPORTIONAL to CURRENT
Case 1: One resistor only
Voltage at AA: 5.22 V
Case 2: Two resistors
Voltage at AA: 5.22 V
* SAME VALUE BECAUSE it is the SUPPLY VOLTAGE
Case 1: One resistor only
Voltage at BB: 1.98 V
Voltage at BB: 2.01 V
Case 2: Two resistors
What did we do by connecting another resistor in parallel?
•Resistance halved
•Current doubled ( V= IR)
But only a …
*VERY SLIGHT VARIATION of VOLTAGE across the LED (0.03 V)
So the DIODE can be a REGULATOR of VOLTAGE
LAB 3 REVIEW
 WHEN A CAPACITOR IS ADDED TO THE
CIRCUIT AND THE SWITCH LEVER IS
PRESSED, THE CAPACITOR VERY QUICKLY
ACQUIRES AND HOLDS AN ELECTRICAL
CHARGE
 WHEN THE SWITCH LEVER IS RELEASED,
THE CAPACITOR HAS TO DISCHARGE
(RELEASE ITS CHARGE) THROUGH THE
RESISTANCE AND THE LED
LAB 3 REVIEW
 SINCE RESISTORS ‘RESIST’ THE FLOW OF
CURRENT, THE LARGER THE RESISTANCE
VALUE, THE LONGER TIME IT TAKES FOR
THE LED TO TURN OFF
 THE CIRCUIT TIME RESPONSE IS ACTUALLY
PROPORTIONAL TO THE PRODUCT OF
RESISTANCE AND CAPACITANCE (RC) AND
THAT PRODUCT IS THE ‘RC TIME
CONSTANT’ FOR THE CIRCUIT
LAB 3 REVIEW
ANY GENERAL DIODE HAS AN
ASSOCIATED FORWARD VOLTAGE
ABOVE WHICH IT CONDUCTS
CURRENT AND BELOW WHICH IT
CONDUCTS VERY LITTLE CURRENT
FOR THE LED WE USED, THE
THRESHOLD OF THE FORWARD
VOLTAGE WAS ABOUT 1.7 VOLTS
LAB 3 REVIEW
 THE TIME FOR THE LED TO TURN OFF
(VOLTAGE DECREASE TO 1.7 VOLTS)
WOULD NOMINALLY BE TWICE AS LONG IF
THE RESISTANCE INVOLVED IS DOUBLED
 TIMES WITH ONE RESISTOR SHOULD BE
NOMINALLY DOUBLE THE TIMES WHEN
TWO RESISTORS ARE IN PARALLEL
TYPES OF
ELECTRONIC DATA SYSTEMS
 DIGITAL
 OPERATION EXHIBITS A FINITE NUMBER OF
DISCRETE CONDITIONS OR SAMPLES (e.g.,
ON/OFF) AND IS RELATIVELY INSENSITIVE
TO NOISE
 ANALOG
 OPERATION EXHIBITS AN INFINITE NUMBER
OF DIFFERENT CONDITIONS AND IS
RELATIVELY SENSITIVE TO NOISE
 HYBRID
 MIXED DIGITAL/ANALOG
ELEMENTS OF AN ELECTRONIC
DATA SYSTEM
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TRANSDUCERS (SENSORS)
SIGNAL CONDITIONING
DATA PROCESSING and CONTROL
ACTUATORS
DATA DISPLAY AND/OR
RECORDING
 ELECTRICAL POWER SOURCE
 CONNECTION OF ELEMENTS
BASIC DATA SYSTEM SCHEMATIC
SENSORS
SIGNAL
CONDITIONING
DATA
PROCESSING
and CONTROL
FROM PROCESS
DISPLAYING
RECORDING
ACTUATORS
TO PROCESS
ELECTRICAL
POWER
TRANSDUCERS
 TRANSDUCERS (SENSORS) are used to
TRANSLATE a MEASURABLE
PROPERTY into a USEABLE (usually
electrical) FORM
 A few MEASURABLE PROPERTIES are:
• PRESSURE
• TEMPERATURE
• STRAIN
• FORCE
• MOMENT
• ACCELERATION
• FREQUENCY
• SIZE
TRANSDUCERS
Strain Gages
Photos from Omega, Inc website
Thermocouples
and Temperature
Probes
TRANSDUCERS
Pressure Transducers
Photos from Omega, Inc website
SIGNAL CONDITIONING
 PROVIDES VERY STABLE POWER
SOURCE
 AMPLIFIES THE SIGNAL (makes it
‘stronger’ and more useable)
 FILTERS THE SIGNAL (‘cleans it up’)
 EXHIBITS LOW OUTPUT IMPEDANCE
(good for noise insensitivity)
DATA PROCESSING and CONTROL
 ROUTING or MANIPULATION of DATA SIGNAL
OCCURRING AFTER SIGNAL CONDITIONING
 COMMONLY INCLUDES CONVERSION to a
DIGITAL SYSTEM (for processing by computer)
 CONTROL SECTION (actuator control)
 DISPLAY and/or RECORDING of the DATA are
GENERALLY the FINAL PROCESSES
ACTUATORS
AN ACTUATOR is a DEVICE which
PERFORMS an ACTION to INFLUENCE a
PROCESS
ACTUATORS
DPDT Relay
Solenoid Valve
SOLENOID VALVE PICTURE FROM SNAP-TITE,
INC. WEBSITE
RELAY PICTURE FROM RADIO SHACK WEBSITE
ACTUATORS
DC Gear Motor
Permanent
Magnet DC
Motor
Photos from Peerless-Winsmith, Inc website
DISPLAY and RECORDING
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STRIP CHARTS
COUNTERS
DIGITAL MULTIMETERS
OSCILLOSCOPES
COMPUTERS
DISPLAY and RECORDING
Counter
Strip-chart recorder
DISPLAY and RECORDING
Digital Multimeter
Oscilloscope
DISPLAY and RECORDING
Computer system
Picture from RadioShack Web site
ELECTRICAL POWER SOURCES
 CHEMICAL
 BATTERIES
 FUEL CELLS
 ELECTRICAL
 AC TO DC POWER SUPPLIES
 DC TO DC POWER SUPPLIES
 MECHANICAL
 GENERATORS
 ALTERNATORS
 SOLAR
 PHOTOVOLTAIC CELL (PV) SYSTEMS
CONNECTION OF ELEMENTS
PERMANENT or TEMPORARY
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HARD WIRE (copper or optical)
LIGHT BEAMS
ULTRASOUND
RADIO FREQUENCY (RF)
Assignment
Read Lab 4 procedure carefully