Volts, Ohms and Amps
Electrical
Measurements
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Electrical Measurements
 Dedicated meters have been used for electrical
measurements.
 Voltmeters measure Volts.
 Ohmmeters measure Ohms.
 Ammeters measure Amps or milliAmps.
 That’s a lot of meters to carry around with us.
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Multimeter
 One device will measure Volts, Ohms, Amps and milliAmps.
 Some have the ability to measure other electrical items such
as:
 Capacitance & Inductance
 Lumens (light)
 Temperature & Sound
 Bipolar transistor function
 Multimeters can be fairly inexpensive <$30
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Multimeter Basics
 Display – Where your
results will be shown.
DISPLAY
 Function Selection Dial –
Use this to select
between Volts, Ohms,
Amps, etc.
 Lead Connection points –
Where you plug in your
leads for the type of
measurements being
conducted.
FUNCTION
SELECTION
DIAL
LEAD
CONNECTION
POINTS
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Function Selection Dial
 The dial on the left is set to DC VOLTS, the dial on the right is
set to AC & DC AMPS
 The meter is Auto-Ranging and automatically selects the
proper range for your measurement.
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Volts
1. Turn the Function Selection Dial
to DC Volts
2. Put the Red Lead into the
V/ohm/mA terminal
3. Put the Black Lead into the COM
terminal.
4. Place the leads in Parallel with
the device being measured.
BLACK
LEAD
HERE
RED
LEAD
HERE
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Ohms
 Turn the Function Selection Dial to
Ohms (Ω)
 The meter leads should be
connected the same as for Volts.
See the red lights.
 Connect your leads together to
make sure it reads zero instead of
OL.
BLACK
LEAD
HERE
RED
LEAD
HERE
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Amps
1. Turn the Function
Selection Dial to AMPS
2. Put the Red Lead into the
10A terminal
3. Put the Black Lead into the
COM terminal.
4. Put the leads in SERIES
with your load.
RED
LEAD
HERE
BLACK
LEAD
HERE
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MilliAmps
 Turn the Function Selection Dial to
mA
 Some meters require you to move
the leads for milliAmps and amp,
others do not.
 You can also measure milliAmps
with the amps scale at reduced
accuracy.
RED
LEAD
HERE
BLACK
LEAD
HERE
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WARNING!!!
 While making measurements you MUST first make sure
your meter is properly set up for the type of measurement
you are making.
 DO NOT quickly switch back and forth between amps and
volts without changing your meter leads.
 Multi-functions come at the expense of possibly destroying
your circuit or your meter.
 If you measure voltage while set to amps, you can blow a
fuse, short out components, cause sparks and arks and
generally become a short order fry cook.
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Measurement Basics
 Voltage – Leads are placed in parallel with the item being
measured. Red to positive, black to negative.
 Ohms – Measurements are made without power. If you need
to measure an individual component, you may need to remove
it from the circuit.
 Amps – Leads are placed in series with the device being
measured.
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