Introduction to EngineeringLab 4 – 1Basic Data Systems & Circuit Prototyping
Agenda REVIEW OF LAB 3 RESULTS DEFINE a DATA SYSTEM
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
Case 2: Two resistors Voltage at BB: 2.01 V
*VERY SLIGHT VARIATION of VOLTAGE across the LED (0.03 V)
What did we do by connecting another resistor in parallel?•Resistance halved•Current doubled ( V= IR)
But only a …
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
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 CONDITION
-ING
DATA PROCESSING
and CONTROL
DISPLAYING
ELECTRICAL POWER
RECORDING
ACTUATORSTO
PROCESS
FROM PROCESS
TRANSDUCERS
TRANSDUCERS (SENSORS) are used to TRANSLATE a MEASURABLE PROPERTY into a USEABLE (usually electrical) FORM
A few MEASURABLE PROPERTIES are:
• MOMENT
• ACCELERATION
• FREQUENCY
• SIZE
•PRESSURE
•TEMPERATURE
•STRAIN
•FORCE
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
SOLENOID VALVE PICTURE FROM SNAP-TITE, INC. WEBSITE
Solenoid Valve
RELAY PICTURE FROM RADIO SHACK WEBSITE
DPDT Relay
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
HARD WIRE (copper or optical) LIGHT BEAMS ULTRASOUND RADIO FREQUENCY (RF)
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