What is a
multimeter?
•A
multimeter is a devise used to measure voltage, resistance and current in
electronics & electrical equipment
•It is also
used to test continuity between to 2 points to verify if there is any breaks in
circuit or line
•There are
two types of multimeter Analog & Digital
–Analog has
a needle style gauge
–Digital has a LCD display (Referenced during
this PPT)
Meter leads
•Red meter lead Is connected to
Voltage/Resistance or amperage port Is considered the positive connection
•Black meter
lead Is always connected to the common port Is considered the negative
connection
•Probes Are
the handles used to hold tip on the tested connection
•Tips Are at
the end of the probe and provides
Measuring Voltage
•Voltage (V)
is the unit of electrical pressure; one volt is the potential difference needed
to cause one amp of current to pass through one ohm of resistance
•Voltage is
broke up into 2 sections AC & DC
Alternating
Current (AC) is house voltage (110/220vac)
Direct
Current (DC) is battery voltage (12vdc)
•Be very
careful to not touch any other electronic components within the equipment and
do not touch the tips to each other while connected to anything else
•To measure
voltage connect the leads in parallel between the two points where the
measurement is to be made. The multimeter provides a parallel pathway so it
needs to be of a high resistance to allow as little current flow through it as
possible
Measuring
Resistance and Continuity
·
Resistance (Ω ) is the opposition to current
•Resistance
is measured in Ohm's
•Disconnect
power source before testing
•Remove
component or part from system before testing
•Measure
using lowest value, if OL move to next level
•Testing for
continuity is used to test to verify if a circuit, wire or fuse is complete
with no open
•Audible
continuity allows an alarm if circuit is complete
•If there is
no audible alarm resistance of 1ohm to .1ohm should be present
Measuring
Current
•Current
(amps) is the flow of electrical charge though a component or conductor
•Current is
measured in amps or amperes
•Disconnect
power source before testing
•Disconnect
completed circuit at end of circuit
•Place
multimeter in series with circuit
•Reconnect
power source and turn ON
•Select
highest current setting and work your way do
