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

TRANSDUCERS

Strain Gages Thermocouples and

Temperature ProbesPhotos from Omega, Inc website

TRANSDUCERS

Pressure TransducersPhotos 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

Solenoid Valve

RELAY PICTURE FROM RADIO SHACK WEBSITE

DPDT Relay

ACTUATORS

DC Gear Motor

Permanent Magnet DC

Motor

Photos from Peerless-Winsmith, Inc website

DISPLAY and RECORDING

STRIP CHARTS COUNTERS DIGITAL MULTIMETERS OSCILLOSCOPES COMPUTERS

DISPLAY and RECORDING

Strip-chart recorder

Counter

DISPLAY and RECORDING

Digital Multimeter Oscilloscope

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