Transcript Have Fun Teaching Electrical

Have Fun Teaching Electrical
Jim Halderman
Introduction
• Former flat-rate
technician
• Former automotive
college instructor
• Author of many
automotive textbooks
• Still plays with cars
• Lives in Dayton, Ohio
Topics to be Discussed
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Meter usage made fun
Wire repair-meter fuse
Project-based learning
LED test light
Memory saver
Speaker tester
Theft deterrent
Logic probe
Why do students take Automotive?
• Not to do math
problems
• Not to learn a lot of
theory
• They attend to learn
how things work
• They want hands-on
activities
Where do I start?
• Touching a battery
• Many in the class would
not touch the terminals
• Gives them the “handson” knowledge of:
• Battery voltage (low)
• Body resistance (high)
You can’t see or feel electricity
• They have to measure
electricity
• Voltage is the most
commonly used
measurement specified
Measure voltage on
their vehicles
CAT III Meters and Leads
Voltage Testing
• DC Volts is the most
commonly used
• A “V” with a straight
line above it.
• AC volts is a V with a
wavy line on top
Series Demonstration
• A typical nine-volt
battery contains six 1.5
volt AAAA batteries
connected in series.
• The voltage adds would
connected in series (1.5
X 6= 9 Volts)
• Students will never
forget this
Dry Cell Battery Drop Test
• Good battery- stays up
or bounces once
• Discharged batterybounces several times
• Does not always work
• Use a voltmeter
Measure body resistance
• Gets students to use
the meter
• Should them the Ohms
symbol
• Show them where to
place the test leads
• How much is normal?
Need to measure k-Ohms
• Normal body resistance
is 200k to 400k Ohms
• If lower means
dehydrated
• Can be over one million
so they will measure 1.1
Meg Ohms which really
confuses them
Meter Settings
Meter scales
What the meter reading means
• Think of MONEY!
• 1.00 = a dollar
0.50= fifty cents or a half dollar
• 0.25 = quarter
• 0.01 = a penny
• Milliamps I compare to thousandth of an inch
such as bearing clearance.
• 0.020 amp is like 20 thousandth of an inch
Ammeter
Test Lead Connections
Protect the meter
• Fuse the meter lead
• Saves money because
the expensive internal
fuse will be protected.
• Use a 10 A. Fuse
• Tie a knot in the leadskeeps them from
getting tangled
Project Based Learning
• The first week, students
get a meter.
• We use the meter every
day starting with
checking their body
resistance.
• Asked to purchase some
low cost electrical parts
that they can use to
build projects for their
project grade
Speaker Tester
• Uses a 1.5 volt battery
• Connect to the speaker
terminals
• If positive (+) is to the
positive terminal, the
speaker cone moves
away for the coil
Air Bag Diagnostic Tool
• Use a 2Ω ½ watt
resistor as “load tool” to
replace a module
• Most modules measure
1.5 to 3.5 Ohms
Shorting Bars
• When an air bag
module is disconnected,
spring-loaded shorting
bars short the two
terminals together
• Use stir straw to cover
one of the shorting bars
Lighter Plug Tester
• Uses a double banana
plug
• Terminals are ¾ inch
apart-the same for all
meters
• Lighter plug
• Some wire
Lighter Plug Tester Usage
Domestic vehiclesLighter (power)plug is
“hot” at all times
Import brandsControlled through the
ignition
Using the lighter Plug-#1
Battery Testing• Connect and watch voltmeter and turn on
high beam headlights.
• Watch voltage drop
• After it stabilizes, turn off the lights
• Watch how fast the voltage increases
• The final voltage is the SOC.
Using the lighter Plug-#2
Cranking voltage• Crank the engine
• Observe the battery voltage
• Should be above 9.6 Volts during cranking
Using the lighter Plug-#3
Charging Voltage• Start the engine and observe the voltmeter
• Should be 13.5-15.0 Volts
Using the lighter Plug-#4
AC Ripple Voltage• Start the engine
• Turn on the headlights to provide an electrical
load
• Switch meter to read AC volts
• Should be less than 0.5 Volt
Diodes
• I do not wait to get to
the electronics part of
the course to teach
diodes
• Most students can
easily understand a
diode
LEDs
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Red
Green
Blue
Anode (+)
Cathode (-)
“A” comes before “C” so
the anode is the
positive and the
cathode is the negative
LED Test Light
• One LED
• One 470Ω ½ W resistor
• A clicker style pen
• Some wire etc.
Memory Saver
• Very popular
• Can be used with a 9Volt battery
• Can be connected to a
jump box
OBD II DLC Memory Saver
• Use OBD II male
connector…Pin #4(-)
and #16(+) to lighter
plug and to a jump box
Theft Deterrent
• Very popular
• Many students build
this and install on their
own vehicle
• Easy to build
• How does it work?
Logic Probe
• Use to check for power
and ground
• A test light can only
detect power (unless
connected to power)
Parts List
PROJECT #1 (Air Bag load tool)
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2 ohm resistor and label
One stir stick straw
PROJECT #2 (Speaker tester)
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Battery holder
PROJECT #3 (Lighter plug test tool)
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Double banana plug
Lighter plug (male end with wire) –
need to cut and strip wire
Two black cable ties
Pocket screwdriver
PROJECT #4 (LED test light)
• LED
• 470 ohm resistor-1/2 Watt
• Two stripped wires
• 1 wire nut
PROJECT #5 (Logic probe)
• One red LED
• One green LED
• Two-470 ohm resistors
• Three stripped wires
• 3 wire nuts
Parts and Prices
Parts and Prices #2
Electrical parts suppliers that I use
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www.amazon.com
www.vetco.net
www.meci.com (Mendelsons)
www.parts-express.com
www.radioshack.com
Summary
• Students love hands-on activities
• I try to get their hands on meters as soon as
possible
• I give them projects that they can make using
low-cost parts.
• Projects that are useful
• Have fun teaching electrical
Contact Information
• [email protected]
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For a copy of this presentation go to:
www.jameshalderman.com
Click on “Jim’s Stuff”
Click on “Conference Power Points”