Extech Instruments EX410 User manual

User's Guide
Digital Multimeter
Extech 410

EX410-EU_ENG V5.1 10/072
Introduction
Congratulations on your purchase of the Extech EX410 Multimeter. This meter measures
AC/DC Voltage, AC/DC Current, Resistance, Diode Test, and Continuity plus Thermocouple
Temperature. Proper use and care of this meter will provide many years of reliable service.
Safety
International Safety Symbols
This symbol, adjacent to another symbol or terminal, indicates the user
must refer to the manual for further information.
This symbol, adjacent to a terminal, indicates that, under normal use,
hazardous voltages may be present
Double insulation
This WARNING symbol indicates a potentially hazardous situation, which
if not avoided, could result in death or serious injury.
This CAUTION symbol indicates a potentially hazardous situation, which
if not avoided, may result damage to the product.
This symbol advises the user that the terminal(s) so marked must not be
connected to a circuit point at which the voltage with respect to earth
ground exceeds (in this case) 600 VAC or VDC.
WARNING
CAUTION
MAX
600V

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CAUTIONS
•Improper use of this meter can cause damage, shock, injury or death. Read and
understand this user manual before operating the meter.
•Always remove the test leads before replacing the battery or fuses.
•Inspect the condition of the test leads and the meter itself for any damage before
operating the meter. Repair or replace any damage before use.
•Use great care when making measurements if the voltages are greater than 25VAC
rms or 35VDC. These voltages are considered a shock hazard.
•Warning! This is a class A equipment. This equipment can cause interferences in the
living quarters; in this case the operator can be required to carry out adequate
measures.
•Always discharge capacitors and remove power from the device under test before
performing Diode, Resistance or Continuity tests.
•Voltage checks on electrical outlets can be difficult and misleading because of the
uncertainty of connection to the recessed electrical contacts. Other means should be
used to ensure that the terminals are not "live".
•If the equipment is used in a manner not specified by the manufacturer, the protection
provided by the equipment may be impaired.
•This device is not a toy and must not reach children’s hands. It contains hazardous
objects as well as small parts that the children could swallow. In case a child
swallows any of them, please contact a physician immediately
•Do not leave batteries and packing material lying around unattended; they can be
dangerous for children if they use them as toys
•In case the device is going to be unused for an extended period of time, remove the
batteries to prevent them from training
•Expired or damaged batteries can cause cauterization on contact with the skin.
Always, therefore, use suitable hand gloves in such cases
•See that the batteries are not short-circuited. Do not throw batteries into the fire.

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OVERVOLTAGE CATEGORY III
This meter meets the IEC 610-1-2001 standard for OVERVOLTAGE CATEGORY III. Cat III
meters are protected against overvoltage transients in fixed installation at the distribution
level. Examples include switches in the fixed installation and some equipment for industrial
use with permanent connection to the fixed installation.
SAFETY INSTRUCTIONS
This meter has been designed for safe use, but must be operated with caution. The rules
listed below must be carefully followed for safe operation.
1. NEVER apply voltage or current to the meter that exceeds the specified maximum:
Input Protection Limits
Function Maximum Input
VAC 750V DC/AC
V DC or V AC 1000V DC/AC, 200Vrms on 200mV range
mA DC 200mA 250V fast acting fuse
A DC 20A 250V fast acting fuse(30 seconds max every 15
minutes)
Ohms, Continuity 250Vrms for 15sec max
2. USE EXTREME CAUTION when working with high voltages.
3. DO NOT measure voltage if the voltage on the "COM" input jack exceeds 600V above
earth ground.
4. NEVER connect the meter leads across a voltage source while the function switch is in
the current, resistance, or diode mode. Doing so can damage the meter.
5. ALWAYS discharge filter capacitors in power supplies and disconnect the power when
making resistance or diode tests.
6. ALWAYS turn off the power and disconnect the test leads before opening the covers to
replace the fuse or battery.
7. NEVER operate the meter unless the back cover and the battery cover is in place and
fastened securely.

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Controls and Jacks
1. Rubber holster
2. 2000 count LCD display
3. °F button
4. °C button
5. Function switch
6. mA, uA and A input jacks
7. COM input jack
8. Positive input jack
9. Battery check button
10. Hold button
11. Backlight button
Note: Tilt stand and battery compartment are on rear of unit.
Symbols and Annunciators
•))) Continuity
Diode test
Battery status
Test lead connection
error
µ micro (10-6) (amps)
m milli (10-3) (volts, amps)
k kilo (103) (ohms)
M mega (106) (ohms) Ω Ohms
A Amps V Volts
AC Alternating current AUTO Autoranging
DC Direct current HOLD Display hold
ºF Degrees Fahrenheit ºC Degrees Centigrade

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Operating Instructions
WARNING: Risk of electrocution. High-voltage circuits, both AC and DC, are very
dangerous and should be measured with great care.
1. ALWAYS turn the function switch to the OFF position when the meter is not in use.
2. If “1 ” appears in the display during a measurement, the value exceeds the range you
have selected. Change to a higher range.
NOTE: On some low AC and DC voltage ranges, with the test leads not connected to a
device, the display may show a random, changing reading. This is normal and is caused by
the high-input sensitivity. The reading will stabilize and give a proper measurement when
connected to a circuit.
DC VOLTAGE MEASUREMENTS
CAUTION: Do not measure DC voltages if a motor on the circuit is being switched ON or
OFF. Large voltage surges may occur that can damage the meter.
1. Set the function switch to the highest V DC ( ) position.
2. Insert the black test lead banana plug into the negative COM
jack.
Insert the red test lead banana plug into the positive Vjack.
3. Touch the black test probe tip to the negative side of the
circuit.
Touch the red test probe tip to the positive side of the circuit.
4. Read the voltage in the display. Reset the function switch to
successively lower V DC positions to obtain a higher
resolution reading. If the polarity is reversed, the display will
show (-) minus before the value.

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AC VOLTAGE MEASUREMENTS
WARNING: Risk of Electrocution. The probe tips may not be long enough to contact the
live parts inside some 240V outlets for appliances because the contacts are recessed
deep in the outlets. As a result, the reading may show 0 volts when the outlet actually has
voltage on it. Make sure the probe tips are touching the metal contacts inside the outlet
before assuming that no voltage is present.
CAUTION: Do not measure AC voltages if a motor on the circuit is being switched ON or
OFF. Large voltage surges may occur that can damage the meter.
1. Set the function switch to the highest V AC ( ) position.
2. Insert the black test lead banana plug into the negative COM
jack.
Insert red test lead banana plug into the positive Vjack.
3. Touch the black test probe tip to the neutral side of the circuit.
Touch the red test probe tip to the “hot” side of the circuit.
4. Read the voltage in the display. Reset the function switch to
successively lower V AC positions to obtain a higher
resolution reading.
DC CURRENT MEASUREMENTS
CAUTION: Do not make current measurements on the 20A scale for longer than 30
seconds. Exceeding 30 seconds may cause damage to the meter and/or the test leads.
1. Insert the black test lead banana plug into the negative
COM jack.
2. For current measurements up to 200µA DC, set the
function switch to the 200µA DC ( )position and
insert the red test lead banana plug into the uA/mA
jack.
3. For current measurements up to 200mA DC, set the
function switch to the 200mA DC position and insert the
red test lead banana plug into the uA/(mA jack.
4. For current measurements up to 20A DC, set the
function switch to the 20A DC range and insert the red
test lead banana plug into the 20A jack.
5. Remove power from the circuit under test, then open up
the circuit at the point where you wish to measure
current.
6. Touch the black test probe tip to the negative side of
the circuit.
Touch the red test probe tip to the positive side of the
circuit.
7. Apply power to the circuit.
8. Read the current in the display.

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AC CURRENT MEASUREMENTS
CAUTION: Do not make current measurements on the 20A scale for longer than 30
seconds. Exceeding 30 seconds may cause damage to the meter and/or the test leads.
1. Insert the black test lead banana plug into the negative
COM jack.
2. For current measurements up to 200mA AC, set the
function switch to the highest 200mA AC ( ) position
and insert the red test lead banana plug into the mA
jack.
3. For current measurements up to 20A AC, set the
function switch to the 20A AC range and insert the red
test lead banana plug into the 20A jack.
4. Remove power from the circuit under test, then open up
the circuit at the point where you wish to measure
current.
5. Touch the black test probe tip to the neutral side of the
circuit.
Touch the red test probe tip to the “hot” side of the
circuit.
6. Apply power to the circuit.
7. Read the current in the display.
RESISTANCE MEASUREMENTS
WARNING: To avoid electric shock, disconnect power to the unit under test and
discharge all capacitors before taking any resistance measurements. Remove the battery
and unplug the line cords.
1. Set the function switch to the highest Ω position.
2. Insert the black test lead banana plug into the negative
COM jack.
Insert the red test lead banana plug into the positive Ωjack.
3. Touch the test probe tips across the circuit or part under test.
It is best to disconnect one side of the part under test so the
rest of the circuit will not interfere with the resistance
reading.
4. Read the resistance in the display and then set the function
switch to the lowest Ωposition that is greater than the actual
or any anticipated resistance.

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CONTINUITY CHECK
WARNING: To avoid electric shock, never measure continuity on circuits or wires that have
voltage on them.
1. Set the function switch to the position.
2. Insert the black lead banana plug into the negative COM
jack.
Insert the red test lead banana plug into the positive Ωjack.
3. Touch the test probe tips to the circuit or wire you wish to
check.
4. If the resistance is less than approximately 150Ω, the
audible signal will sound. If the circuit is open, the display
will indicate “1”.
DIODE TEST
1. Insert the black test lead banana plug into the negative
COM jack and the red test lead banana plug into the
positive diode jack.
2. Turn the rotary switch to the position.
3. Touch the test probes to the diode under test. Forward
bias will typically indicate 400 to 1000. Reverse bias will
indicate “1 ”. Shorted devices will indicate near 0 and the
continuity beeper will sound. An open device will indicate
“1 ” in both polarities.

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TEMPERATURE MEASUREMENTS
1. Set the function switch to the TEMP position.
2. Insert the Temperature Probe into the
Temperature Socket, making sure to observe
the correct polarity.
3. Press the ºC or ºF button for the desired units.
4. Touch the Temperature Probe head to the
part whose temperature you wish to measure.
Keep the probe touching the part under test
until the reading stabilizes.
5. Read the temperature in the display.
Note: The temperature probe is fitted with a type
K mini connector. A mini connector to
banana connector adaptor is supplied for
connection to the input banana jacks.
DISPLAY BACKLIGHT
Press and hold the button to turn on the display backlight function. The backlight will
automatically turn off after 15 seconds.
BATTERY CHECK
The CHECK function tests the condition of the 9V battery. Set the function switch to
the 200VDC range and press the CHECK button. If the reading is less than 8.5, battery
replacement is recommended.
HOLD
The hold function freezes the reading in the display. Press the HOLD key momentarily to
activate or to exit the hold function.
AUTO POWER OFF
The auto off feature will turn the meter off after 15 minutes.
LOW BATTERY INDICATION
If the icon appears in the display, the battery voltage is low and the battery should be
replaced.
WRONG CONNECTION INDICATION
The icon will appear in the upper right conner of the display and the buzzer will sound
whenever the positive test lead is inserted into the 20A or uA/mA input jack and a non-
current (green) function is selected. If this occurs, turn the meter off and reinsert the test
lead into the proper input jack for the function selected.