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Introduction to Engineering Lab 4 – 1 Basic 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
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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
Voltage at AA: 5.22 V Case 1: One resistor only Case 2: Two resistors Voltage at AA: 5.22 V * SAME VALUE BECAUSE it is the SUPPLY VOLTAGE
Voltage at BB: 1.98 V Case 1: One resistor only 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 • TRANSDUCERS (SENSORS) • SIGNAL CONDITIONING • DATA PROCESSING and CONTROL • ACTUATORS • DATA DISPLAY AND/OR RECORDING • ELECTRICAL POWER SOURCE • CONNECTION OF ELEMENTS
BASIC DATA SYSTEM SCHEMATIC SIGNAL CONDITION-ING DATA PROCESSING and CONTROL SENSORS DISPLAYING FROM PROCESS RECORDING ACTUATORS TO PROCESS ELECTRICAL POWER
TRANSDUCERS (SENSORS) are used to TRANSLATE a MEASURABLE PROPERTY into a USEABLE (usually electrical) FORM A few MEASURABLE PROPERTIES are: MOMENT ACCELERATION FREQUENCY SIZE TRANSDUCERS • PRESSURE • TEMPERATURE • STRAIN • FORCE
TRANSDUCERS Strain Gages Thermocouples and Temperature Probes Photos from Omega, Inc website
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 SOLENOID VALVE PICTURE FROM SNAP-TITE, INC. WEBSITE DPDT Relay Solenoid Valve RELAY PICTURE FROM RADIO SHACK WEBSITE
ACTUATORS DC Gear Motor Permanent Magnet DC Motor Photos from Peerless-Winsmith, Inc website
DISPLAY and RECORDING • STRIP CHARTS • COUNTERS • DIGITAL MULTIMETERS • OSCILLOSCOPES • COMPUTERS Ca
DISPLAY and RECORDING Counter Strip-chart recorder
DISPLAY and RECORDING Oscilloscope Digital Multimeter
DISPLAY and RECORDING Picture from RadioShack Web site Computer system
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)
Assignment • Read Lab 4 procedure carefully