Extech Instruments 411 User manual

User's Guide
True RMS Multimeter
Extech 411

V4.0 5/072
Introduction
Congratulations on your purchase of the Extech 411 (part number
EX411) True RMS 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
This symbol adjacent to another symbol,
terminal or operating device indicates that the
operator must refer to an explanation in the
Operating Instructions to avoid personal injury
or damage to the meter.
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)
1000 VAC or VDC.
This symbol adjacent to one or more terminals
identifies them as being associated with
ranges that may, in normal use, be subjected
to particularly hazardous voltages. For
maximum safety, the meter and its test leads
should not be handled when these terminals
are energized.
This symbol indicates that a device is
protected throughout by double insulation or
reinforced insulation.
WARNING
CAUTION
MAX
1000V

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OVERVOLTAGE CATEGORY III
This meter meets the IEC 610-1-95 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 1000V 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. Degrees F button
4. Degrees 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

V4.0 5/075
Specifications
Function Range
Resolution Accuracy
200mV 0.1mV ±(0.3% reading + 2 digits)
2V 0.001V
200V 0.1V ±(0.5% reading + 2 digits)
DC Voltage
(V DC)
1000V 1V ±(0.8% reading + 2 digits)
50 to 400Hz 400Hz to 1kHz
2V 0.001V
±(1.0% reading
+6 digits
±(2.0% reading
+ 8 digits
200V 0.1V ±(1.5% reading
+6 digits
±(2.5% reading
+8 digits
AC Voltage
(V AC)
(True rms)
750V 1V ±(2.0% reading
+6 digits
±(3.0% reading
+8 digits
200µA 0.1µA
200mA 0.1mA ±(1.5% reading + 3 digits)
DC Current
(A DC)
20A 0.01A
±(2.5% reading + 3 digits)
50 to 400Hz 400Hz to 1kHz
200mA 0.1mA ±(1.8% reading
+8 digits
±(2.5% reading
+10 digits)
AC Current
(A AC)
(True rms)
20A 0.01A
±(3.0% reading
+8 digits)
±(3.5% reading
+10 digits)
200Ω0.1Ω±(0.8% reading +4 digits)
2000Ω1Ω±(0.8% reading +2 digits)
20kΩ0.01kΩ
200kΩ0.1kΩ±(1.0% reading +2 digits)
Resistance
20MΩ0.01MΩ±(2.0% reading +5 digits)
-4 to
1382ºF
1ºFTemperature
-20 to
750ºC
1ºC
±(3.0% reading +3 digits)
(meter only, probe accuracy not
included)
NOTE: Accuracy specifications consist of two elements:
•(% reading) – This is the accuracy of the measurement circuit.
•(+ digits) – This is the accuracy of the analog to digital converter.
NOTE: Accuracy is stated at 65oF to 83oF (18oC to 28oC) and less
than 75% RH.

V4.0 5/076
Specifications
Diode Test Test current of 1mA maximum, open
circuit voltage 2.8V DC typical
Continuity Check Audible signal will sound if the
resistance is less than approximately
150Ω
Input Impedance 10MΩ
AC Response True rms
ACV Bandwidth 50Hz to 1kHz
DCA voltage drop 200mV
Display 3 ½ digit, 2000 count LCD, 0.9” digits
Auto-Power Off 15 minutes (approximately)
Overrange indication “1” is displayed
Polarity Automatic (no indication for positive
polarity); Minus (-) sign for negative
polarity.
Measurement Rate 2 times per second, nominal
Low Battery Indication “ ” is displayed if battery voltage
drops below operating voltage
Battery One 9 volt (NEDA 1604) battery
Fuses mA, µA ranges; 0.2A/250V fast blow
A range; 20A/250V ceramic fast blow
Operating Temperature 41ºF to 104ºF (5ºC to 40ºC)
Storage Temperature -4oF to 140oF (-20oC to 60oC)
Operating Humidity Max 80% up to 87ºF (31ºC)
decreasing linearly to 50% at
104ºF(40ºC)
Storage Humidity <80%
Operating Altitude 7000ft. (2000meters) maximum.
Weight 0.753lb (342g) (includes holster).
Size 7.36” x 3.2” x 2.0” (187 x 81 x 50mm)
(includes holster)
Safety For indoor use and in accordance with
the requirements for double insulation to
IEC1010-1 (1995): EN61010-1 (1995)
Overvoltage Category III 600V and
Category II 1000V, Pollution Degree 2.

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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.

V4.0 5/078
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.

V4.0 5/079
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.

V4.0 5/0710
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.

V4.0 5/0711
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.

V4.0 5/0712
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.

V4.0 5/0713
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 ºF or ºC
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.

V4.0 5/0714
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.

V4.0 5/0715
Maintenance
WARNING: To avoid electric shock, disconnect the test leads
from any source of voltage before removing the back cover or
the battery cover.
WARNING: To avoid electric shock, do not operate your meter
until the battery and fuse covers are in place and fastened
securely.
This MultiMeter is designed to provide years of dependable service,
if the following care instructions are performed:
1. KEEP THE METER DRY. If it gets wet, wipe it off.
2. USE AND STORE THE METER IN NORMAL
TEMPERATURES. Temperature extremes can shorten the life
of the electronic parts and distort or melt plastic parts.
3. HANDLE THE METER GENTLY AND CAREFULLY. Dropping
it can damage the electronic parts or the case.
4. KEEP THE METER CLEAN. Wipe the case occasionally with a
damp cloth. DO NOT use chemicals, cleaning solvents, or
detergents.
5. USE ONLY FRESH BATTERY OF THE RECOMMENDED
SIZE AND TYPE. Remove old or weak battery so they do not
leak and damage the unit.
6. IF THE METER IS TO BE STORED FOR A LONG PERIOD
OF TIME, the battery should be removed to prevent damage to
the unit.

V4.0 5/0716
REPLACING THE BATTERY
WARNING: To avoid electric shock, disconnect the test leads
from any source of voltage before removing the battery cover.
1. When the battery becomes exhausted or drops below the
operating voltage, The symbol will appear in the LCD
display when the battery check button is pressed. The battery
should be replaced.
2. Remove the two screws “B” securing the rear battery cover, lift
the cover off and replace the battery.
3. Replace and secure the battery cover.
4. Properly dispose of the old battery.
WARNING: To avoid electric shock, do not operate your meter
until the battery cover is in place and fastened securely.

V4.0 5/0717
REPLACING THE FUSES
WARNING: To avoid electric shock, disconnect the test leads
from any source of voltage before removing the fuse cover.
1. Disconnect the test leads from the meter.
2. Remove the protective rubber holster.
3. Remove the battery cover (two “B” screws) and the battery.
4. Remove the four “A” screws securing the rear cover.
5. Lift the center circuit board straight up from the connectors to
gain access to the fuse holders.
6. Gently remove the old fuse and install the new fuse into the
holder.
7. Always use a fuse of the proper size and value (0.2A/250V fast
blow for the 200mA range, 20A/250V fast blow for the 20A
range).
8. Align the center board with the connectors and gently press
into place.
9. Replace and secure the rear cover, battery and battery cover.
WARNING: To avoid electric shock, do not operate your meter
until the fuse cover is in place and fastened securely.
UL LISTED
The UL mark does not indicate that this product has been
evaluated for the accuracy of its readings.

V4.0 5/0718

Support Hotline [phone]
Tech support: Ext. 200; Email: [email protected]
Repair/Returns: Ext. 210; Email: [email protected]
Website: www.extech.com
Warranty
EXTECH INSTRUMENTS CORPORATION warrants this instrument to be free of
defects in parts and workmanship for one year from date of shipment (a six month
limited warranty applies on sensors and cables). If it should become necessary to
return the instrument for service during or beyond the warranty period, contact the
Customer Service Department at [phone] ext. 210 for authorization or visit our
website at www.extech.com (click on ‘Contact Extech’ and go to ‘Service Department’
to request an RA number). A Return Authorization (RA) number must be issued before
any product is returned to Extech. The sender is responsible for shipping charges,
freight, insurance and proper packaging to prevent damage in transit. This warranty
does not apply to defects resulting from action of the user such as misuse, improper
wiring, operation outside of specification, improper maintenance or repair, or
unauthorized modification. Extech specifically disclaims any implied warranties or
merchantability or fitness for a specific purpose and will not be liable for any direct,
indirect, incidental or consequential damages. Extech's total liability is limited to repair
or replacement of the product. The warranty set forth above is inclusive and no other
warranty, whether written or oral, is expressed or implied.
Calibration and Repair Services
Extech offers complete repair and calibration services for the
products we sell. For periodic calibration, NIST certification or
repair of an Extech product, call customer service for details on
services available for that product. Extech recommends that
calibration be performed on an annual basis to ensure
calibration integrity.
Copyright ©2003 Extech Instruments Corporation.
All rights reserved including the right of reproduction
in whole or in part in any form.