How To Use A Multimeter
Learning how to use a multimeter can be very confusing when you are trying to understand resistance,ohms,continuity and infinity.
The purpose of this page is to teach you (in a non technical way) to use a analog multimeter to test circuits or voltage in or around your home and to check water heater elements and thermostats.
Electrical meters can range in prices from ten dollars to hundreds
of dollars. For home users I recommend a fuse protected meter. If you make
a mistake the fuse will protect the meter.
What is an analog multimeter?
An analog meter uses a needle to measure voltage and continuity.
The analog meter in the pic is very inexpensive and can be used to check AC or DC voltage and continuity.
What is continuity?
Simply put, continuity means uninterrupted or no resistance.
Suppose we test a light switch for continuity. With our meter
dial set on RX1 the needle would sweep across the face of the meter
and stop on zero . This tells us that we have zero resistance. The circuit
on this switch is uninterrupted, 120 volts can flow through this switch.
Now suppose the needle stops half way across the face and does not go to zero. This means that we have resistance or an interruption in the circuit. It could be corrosion or rust or a worn circuit. 120 volts cannot flow through this circuit. The switch should be replaced.
A continuity test is used to check wires,circuits, switches and parts.
If an electrical device has stopped working, the flow of electric has
Setting up your meter to check continuity or resistance.
Set the dial on your multimeter
Touch the two meter probes
together (see pic).
The thumb wheel on the side
of the meter is used to adjust
the needle if it does not stop
How to test a light switch
All continuity test should be done with the power off. Any wires that may interfere with the test should be removed.
Multimeter's have a black
To test a light switch, place a probe on each of the terminal screws.
With the switch off, you should not get a reading.
With the switch on, the needle should sweep over to zero.
How to use a multimeter to check a wall outlet
To check ac voltage set
The ac value on this meter
Always set the value higher than the voltage you're testing.
To check a wall outlet set your meter at a value above 120 volts.
Insert both probes into the
This outlet is reading 120 volts.
Always check your multimeter on
How to read a multimeter when checking DC voltage
To check dc voltage set your dial to dc at a voltage higher than what your checking.
We're going to check a car battery and we know its 12 volts so we'll have to set the valve at 50 volts on this meter.
When checking dc voltage you must use the red probe for positive (+) and the black probe for negative (-)
This car battery is reading
How to use a multimeter - how to read a multimeter
Safety and buying tips for an analog multimeter
Always buy a meter that is fuse protected. If you check something with the meter on the wrong setting the fuse will blow instead of burning up the meter.
Always check your meter before every test to be sure its working
Never trust a multimeter 100 percent when checking ac voltage.
Never touch the metal tips of the multimeter probes when testing.
Set the multimeter value higher than the device you're checking
All continuity test are done with the power off.
Please learn how to use a multimeter safely before checking anything with exposed wires and the power on.
How to check the power coming into your water heater, click here.
Test an electric water heater thermostat, click here.
How to check a water heater element, click here.