Register Digital Multimeter Usage Click Register to begin the
course
Slide 3
Next This lesson is for diagnosing a inoperative light
bulb
Slide 4
Next The first step is to check the source voltage Click on the
Multimeter below to see how to set up the meter
Slide 5
In this lesson, you will learn how to set up a Digital
Multimeter (DMM) to perform various measurements Click on each
question to learn more How is the rotary switch positioned? In
which input jack is the black lead installed? In which input jack
is the red lead installed? Based on the previous questions, what is
the meter set up to measure? How does this meter need to be
connected to a circuit or component (in series or in parallel)?
Should the power in the circuit be on or off to perform this
measurement? Next Digital Multimeter (DMM) Usage DC Voltage Common
Volt/Ohm DC Voltage up to 1000 volts Parallel Power must be turned
on
Slide 6
Next Check Battery Voltage #1 The red meter lead is placed on
the positive terminal of the battery Click on the Meter to place
the red lead The black meter lead is placed on the negative
terminal of the battery Click on the Meter to place the black lead
12 Volts at the battery indicates a good battery source Proceed to
next step in diagnosis < 5 Volts at the battery indicates a bad
battery Fix: Charge or replace battery
Slide 7
Next Check for Voltage at the Switch #2 The red meter lead is
placed on the side of the switch closest to the battery Click on
the Meter to place the red lead The black meter lead is placed on
the negative terminal of the battery Click on the Meter to place
the black lead 12 Volts at switch indicates a good switch Proceed
to next step in diagnosis < 5 Volts at the switch indicates a
bad wire from positive terminal of battery to switch Fix: Replace
Wire from positive terminal of battery to switch
Slide 8
Next Check for Voltage at the Switch #3 The red meter lead is
placed on the other side of the switch Click on the Meter to place
the red lead The black meter lead is placed on the negative
terminal of the battery Click on the Meter to place the black lead
12 Volts at switch indicates a good switch Proceed to next step in
diagnosis < 5 Volts at the switch indicates a bad Switch Fix:
Replace switch
Slide 9
Next Check for Voltage at the Bulb #4 The red meter lead is
placed at the bulb side closest to the battery Click on the Meter
to place the red lead The black meter lead is placed on the
negative terminal of the battery Click on the Meter to place the
black lead 12 Volts at switch indicates a good wire between switch
and bulb Proceed to next step in diagnosis < 5 Volts at the bulb
indicates a bad wire between switch and bulb Fix: Replace wire
between switch and bulb
Slide 10
Next Check for Voltage after the Bulb The red meter lead is
placed on the other side of the bulb Click on the Meter to place
the red lead The black meter lead is placed on the negative
terminal of the battery Click on the Meter to place the black lead
12 Volts at the bulb indicates a good bulb and a bad ground To
verify bad ground do a resistance check on the ground. Click next
to see the meter set up for Ohms 0 Volts at the bulb indicates a
bad bulb Fix: Replace the bulb
Slide 11
In this lesson, you will learn how to set up a Digital
Multimeter (DMM) to perform various measurements Click on each
question to learn more How is the rotary switch positioned? In
which input jack is the black lead installed? In which input jack
is the red lead installed? Based on the previous questions, what is
the meter set up to measure? How does this meter need to be
connected to a circuit or component (in series or in parallel)?
Should the power in the circuit be on or off to perform this
measurement? Next Digital Multimeter (DMM) Usage Ohms Common
Volt/Ohm Resistance displayed in Ohms Parallel Power must be turned
off
Slide 12
Next Check the resistance of the ground wire #5 The red meter
lead is placed on the known good ground Click on the Meter to place
the red lead The black meter lead is placed on the ground circuit
for the bulb Click on the Meter to place the black lead Below 5
indicates a good ground Above 5 indicates a bad ground Fix: Replace
the Ground Wire Disconnect the Power Source Click on the Battery to
Disconnect Power