Extech Instruments DM4750D User manual

Digital Multimeter DM4750D

Introduction
Congratulations on your purchase of the Extech DM4750D Multimeter. This meter measures AC/DC
Voltage, AC/DC Current, Resistance, Diode Test, and Continuity plus Thermocouple Temperature.
This device is shipped fully tested and calibrated and, with proper use, will provide years of reliable
service. Please visit our website (www.extech.com) to check for the latest version of this User Guide,
Product Updates, and Customer Support.
Safety
International Safety Symbols
WARNING
CAUTION
MAX
600V
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.

OVERVOLTAGE CATEGORY III
This meter meets the IEC 61010-1-2001 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
toreplace the fuse or battery.
7. NEVER operate the meter unless the back cover and the battery cover is in place
and fastened securely.

Controls and Jacks
1. Rubber holster (must be removed to access battery)
2. 2000 count LCD display
3. °F button for temperature measurements
4. °C button for temperature measurements
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 (freezes displayed reading)
11. LCD backlight button
Note: Tilt stand, test lead holders, and battery compartment are on rear of unit.
Symbols and Annunciators
•))) Continuity
Diode test
Battery status
Test lead connection error
HOLD Display hold
ºF Degrees Fahrenheit
ºC Degrees Celsius

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.
Specifications
Function
Range
Resolution
Accuracy
DC Voltage
200mV
0.1mV
(0.3% reading + 2 digits)
(V DC)
2V
0.001V
(0.5% reading + 2 digits)
200V
0.1V
1000V
1V
(0.8% reading + 2 digits)
AC Voltage
50 to 400Hz
400Hz to 1kHz
(V AC)
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
750V
1V
(2.0% reading +6 digits
(3.0% reading +8 digits
DC Current
200 A
0.1 A
(1.5% reading + 3 digits)
(A DC)
200mA
0.1mA
20A
0.01A
(2.5% reading + 3 digits)
AC Current
50 to 400Hz
400Hz to 1kHz
(A AC)
200mA
0.1mA
(1.8% reading +8 digits
(2.5% reading +10 digits)
20A
0.01A
(3.0% reading +8 digits)
(3.5% reading +10 digits)
Resistance
200
0.1
(0.8% reading +4 digits)
2000
1
(0.8% reading +2 digits)
20k
0.01k
(1.0% reading +2 digits)
200k
0.1k
20M
0.01M
(2.0% reading +5 digits)
Temperature
-20 to 750ºC
1ºC
(3.0% reading +3 digits)
-4 to 1382ºF
1ºF
(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 18oC to 28oC (65oF to 83oF) and less than 75% RH.

General Specifications
Diode Test
Test current of 1mA maximum, open circuit voltage 2.8V DC typical
Continuity Check
Audible signal when resistance is less than approximately 150
Input Impedance
10MΩ
AC Response
Average responding
ACV Bandwidth
50Hz to 1kHz
DCA voltage drop
200mV
Display
3 ½ digit, 2000 count LCD, 0.9” digits
Auto-Power Off
Meter switches OFF after 15 minutes (approximately) of inactivity
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
5ºC to 40ºC (41ºF to 104ºF)
Storage Temperature
-20ºC to 60ºC (-4ºF to 140ºF)
Operating Humidity
Max 80% up to 31ºC (87ºF) decreasing linearly to 50% at 40ºC (104ºF)
Storage Humidity
<80%
Operating Altitude
2000 meters (7000ft.) maximum
Weight
342g (0.753lb) (includes holster)
Size
187 x 81 x 50mm (7.36” x 3.2” x 2.0”) (includes holster)
Safety
For indoor use and in accordance with the requirements for double
insulation to IEC1010-1 (2001): EN61010-1 (2001) Overvoltage
Category III 600V and Category II 1000V, Pollution Degree 2.