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

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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

Multimeter Basics

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Display – Where your results will be shown.

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.

DISPLAY

LEAD CONNECTION

POINTS

FUNCTION SELECTION

DIAL

Function Selection Dial

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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.

Volts

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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

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.

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RED LEAD HERE

BLACK LEAD HERE

Amps

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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

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.

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BLACK LEAD HERE

RED LEAD HERE

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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