Transcript What is Current? - NYU Polytechnic School of Engineering

SUMMER RESEARCH 2002
Polytechnic University
Mechanical Engineering
ORIENTATION
Introduction
• Professor Vikram Kapila
• Associate Professor
• Room: RH 508
Phone: (718) 260-3161/3160
E-mail: [email protected]
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Name: Nathan (Sang-Hoon) Lee
Room: RH 514A
Phone: (718)260-3783
E-mail: [email protected]
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Teaching assistants
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Name: Isaac Osei
Room: RH 514A
Phone: (718)260-3783
E-mail: [email protected]
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Laboratory rule
• Don’t play
– no e-mail checking, chatting, browsing web, listening
music, singing, running, etc.
• Don’t touch any other experiments
• No food and no drink
• Keep this room clean and well organized
– after experiments, put them in original place with the
same original condition
• Respect each other
• Maturity
• Practice safety
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Schedule
Start Date: July 1, 2002(Monday)
End Date: August 16, 2002(Friday)
Period: 7 weeks
Day: Monday - Friday
Time: 10am - 4pm
Lunch time: 12:40pm – 1:40pm
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Mon
1
1st
Tue
2
8
2nd
Lecture1
Resistors
9
3rd
16
4
17
4th
23
30
5th
5
Holiday
Basic electronic
projects
12
18
Presentation
19
Robotics (6)
24
Brain storming for a project
29
Fri
Basic analog and digital (8)
Earth measurements (6)
22
Thu
Lecture2
Digital multimeter
Lecture3
Signals
10
11
What's a microcontroller? (6)
15
Presentation
25
26
Building the project
31
1
Presentation
2
Building the project
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6
6th
7
Presentation
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9
Building the project
12
7th
3
Orientation
Yes center
schedule
Wed
13
14
Presentation
15
Building the project
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Presentation
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Writing lab report
• Prepare a lab book
• Write what you learned, what you did, what
you needed
• Do this everyday
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Making presentation
• Show what you learned, what you did for a
week on every Friday
• Use Microsoft power point
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How to make a Presentation
Isaac Osei
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Five Steps
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Planning
Introduction
The Body
The Conclusion
Questions
• Presentation Tips
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STEP 1 - Planning
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Topic/Main Idea
Research
Structure
Audience
Time
Outline
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STEP 2 - The INTRODUCTION
• Connection
• Attention
• Preview
• Structure
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STEP 3 - The Body
• Information
• Speak Clearly
• Follow the Outline
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STEP 4 - The Conclusion
• Reinforce
• Summarize
• Conclude
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STEP 5 - Questions
• Important
• Prepare ahead of Time
• Thank your audience
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Tips for Maintaining your
Audience’s Attention
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Make your presentation Interactive
Share Stories
Repetition
Humor
Never Read
Move Around
Eye Contact
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Ice break
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Name
School
Specialty
Hobby
Goal for this summer program
Others
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Making groups
• make 4 groups in total
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Lecture 1
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What is current?
• A flow of charged particles
• Carried by small negatively-charged
particles, called electrons
• Represented by the symbol I, and is
measured in amperes, or 'amps', A.
• Most often measured in milliamps, mA
• Like water flow
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Water analogy
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What is voltage?
• Potential difference, or voltage
• Represented by the symbol V , and is
measured in volts, V
• Like potential energy at water fall
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Water analogy
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Series connection of cells
• Each cell provides 1.5 V. Two cells connected one
after another, in series, provide 3 V, while three
cells would provide 4.5 V
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Parallel connection of cells
• If the cells are connected in parallel, the voltage
stays at 1.5 V, but the life of the battery is doubled
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DC and AC
• A cell provides a steady voltage, so that
current flow is always in the same direction.
This is called direct current, or d.c
• The domestic mains provides a constantly
changing voltage which reverses in polarity
60 times every second. This gives rise to
alternating current, or a.c
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Power Supply
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Resistor
• A dissipative element that converts electrical
energy into heat
• Resistors limit current
• Unit is ohms, W
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resistors of different sizes
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How to read resistor value
1. By color code
2. By digital multi meter(DMM)
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How to read resistor value
1. By color code
Resistor value= AB10C  tol%(W)
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Resistance Color code
Number
0
1
2
3
Color
black
brown
red
orange
4
5
6
7
8
9
yellow
green
blue
violet
grey
white
Tolerance Color
±1%
±2%
±5%
±10%
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brown
red
gold
silver
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example
• The first band is yellow, so the first digit is 4
• Second digit is a violet band, making the second
digit 7
• A red band is 2
2
• Resistor value is 4710  5%(W)
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Metric Units and conversions
Abbreviation Means
p
n
µ
m
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k
M
G
Multiply unit by
Or
pico
.000000000001
nano
.000000001
micro
.000001
milli
.001
Unit
1
kilo
1,000
mega
1,000,000
giga
1,000,000,000
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10 -12
10 -9
10 -6
10 -3
10 0
10 3
10 6
10 9
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example
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Digital multimeter
• Voltmeter
– Parallel connection
• Ammeter
– Series connection
• Ohmmeter
– Without any power supplied
• Adjust range(start from highest
limit if you don’t know)
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Resistors in series
Rtotal=R1+R2
Rtotal=1+1=2kohm
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Resistors in parallel
R1  R2
Rtotal 
R1  R2
1 1 1
Rtotal 
  0.5kW
11 2
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Exercise
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Potentiometer
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Has a adjustable resistance
Circular potentiometer
Linear potentiometer
Use as a position sensor
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Potentiometer
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Potentiometer
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Linear potentiometer
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Linear potentiometer
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Linear potentiometer
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Lecture 2
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Capacitors
• store electric charge
• consists of two plates of a conducting material
separated by a space filled by an insulator
• measured in units called farads, F
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How to read capacitor value
• The first two figures give us 10, the third
figure gives us 0000, and the letter 10%. We
normally express this as 0.1µF
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LED
Light-emitting diodes
Semiconductor
Has polarity
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LEDs
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How to connect LED
• Requires 1.5~2.5V
and 10 miliA
• To prevent overloading,
use resistor(330 ohm)
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breadboard
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breadboard
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Digital multimeter
• A meter is a measuring instrument
• An ammeter measures current
• a voltmeter measures the potential
difference (voltage) between two
points
• an ohmmeter measures resistance
• A multimeter combines these
functions, and possibly some
additional ones as well, into a single
instrument
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Digital multimeter
• Voltmeter
– Parallel connection
• Ammeter
– Series connection
• Ohmmeter
– Without any power supplied
• Adjust range(start from highest
limit if you don’t know)
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switched range multimeter
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Auto ranging multimeter
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Ammeter connection
• Break the circuit so that the ammeter can be connected in series
• All the current flowing in the circuit must pass through the
ammeter
• An ammeter must have a very LOW resistance.
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Voltmeter connection
• The voltmeter is connected in parallel between the two
points
• a voltmeter should have a very HIGH resistance
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Ohmmeter connection
• An ohmmeter does not function with a circuit connected to a
power supply
• must take it out of the circuit altogether and test it separately
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Lecture 3
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DC signals
• A cell provides a steady voltage, so that
current flow is always in the same direction.
This is called direct current, or d.c
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AC signals
• the voltage levels change with time and alternate
between positive values (above the X-axis) and
negative values
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Sine waves
• A sine wave has the same shape as the graph of
the sine function
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Properties of Sine waves
• Period: T : The period is the time taken for
one complete cycle of a repeating waveform
• Frequency: f : This is the number of cycles
completed per second. The measurement unit
for frequency is the hertz, Hz
1
T
f
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Properties of Sine waves
• Amplitude:
– peak amplitude, Vp
– peak-to-peak amplitude, Vpp
– rms amplitude
Vrms
VP
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2
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What is rms amplitude and
why is it important?
• The rms amplitude is the DC voltage which
will deliver the same average power as the
AC signal
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Properties of Sine waves
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Audio signal and noise
• sound frequencies which can be detected by the human
ear vary from a lower limit of around 20 Hz to an upper
limit of about 20 kHz
• A noise signal consists of a mixture of frequencies with
random amplitudes
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waveforms of different frequency
and amplitude
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Function generator
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Connection using a BNC lead
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Oscilloscope
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Oscilloscope
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Screen of a oscilloscope
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VOLTS/DIV and TIME/DIV
of a oscilloscope
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Basic electronic projects
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Micro controller
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Summer 2002 projects
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Summer 2002 projects
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Biotronics
Weather station
Mobile robot
Automobile
Security system
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