Jensen DT-985 User manual

DT-985
TRMS MULTIMETER

2
Introduction
This meter measures AC/DC Voltage, AC/DC Current, Resistance, Capacitance, Frequency
(electrical & electronic), Diode Test, and Continuity plus Thermocouple Temperature. It
features a waterproof, rugged design for heavy duty use. 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.
PER IEC1010 OVERVOLTAGE INSTALLATION CATEGORY
OVERVOLTAGE CATEGORY I
Equipment of OVERVOLTAGE CATEGORY I is equipment for connection to circuits in which
measures are taken to limit the transient overvoltages to an appropriate low level.
Note – Examples include protected electronic circuits.
OVERVOLTAGE CATEGORY II
Equipment of OVERVOLTAGE CATEGORY II is energy-consuming equipment to be supplied
from the fixed installation.
Note – Examples include household, office, and laboratory appliances.
OVERVOLTAGE CATEGORY III
Equipment of OVERVOLTAGE CATEGORY III is equipment in fixed installations.
Note – Examples include switches in the fixed installation and some equipment for industrial
use with permanent connection to the fixed installation.
OVERVOLTAGE CATEGORY IV
Equipment of OVERVOLTAGE CATEGORY IV is for use at the origin of the installation.
Note – Examples include electricity meters and primary over-current protection equipment
WARNIN
G
CAUTIO
N
MA

3
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
V DC or V AC 1000VDC/AC rms
mA AC/DC 800mA 1000V fast acting fuse
A AC/DC
10A 1000V fast acting fuse (
1
0A for 30 seconds
max every 15 minutes)
Frequency, Resistance,
Capacitance, Diode Test,
Continuity
600VDC/AC rms
Temperature
6
00VDC/AC rms
Surge Protection: 8kV peak per IEC 61010
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 batteries.
7. NEVER operate the meter unless the back cover and the battery and fuse covers are in
place and fastened securely.
8. If the equipment is used in a manner not specified by the manufacturer, the protection
provided by the equipment may be impaired.

4
Controls and Jacks
1. 6,000 counts LCD Negativity display
2. MAX/MIN button
3. RANGE button
4. Mode button
5. Function switch
6. mA, µA and 10A input jacks
7. COM input jack
8. Positive input jack
9. HOLD and Backlight button
10. Hz and % button
11. RELATIVE button
12. Battery Cover
Note: Tilt stand and battery compartment are on rear of unit.

5
Symbols and Annunciators
Auto power off
•))) Continuity
Diode test
Battery status
n nano (10-9) (capacitance)
µ micro (10-6) (amps, cap)
m milli (10-3) (volts, amps)
A Amps
k kilo (103) (ohms)
F Farads (capacitance)
M mega (106) (ohms)
Ohms
Hz Hertz (frequency)
V Volts
% Percent (duty ratio)
REL Relative
AC Alternating current
AUTO Autoranging
DC Direct current
HOLD Display hold
ºF Degrees Fahrenheit
ºC Degrees Centigrade
MAX Maximum
MIN Minimum

6
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 “OL” appears in the display during a measurement, the value exceeds the range you have
selected. Change to a higher range.
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 green VDC position.
2. Insert the black test lead banana plug into the negative COM jack.
Insert the red test lead banana plug into the positive V jack.
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.
AC VOLTAGE (FREQUENCY, DUTY CYCLE) 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 green VAC/Hz/% position.
2. Insert the black test lead banana plug into the negative COM jack.
Insert red test lead banana plug into the positive V jack.
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.
5. Press the HZ/% button to indicate “Hz”.
6. Read the frequency in the display.
7. Press the Hz/% button again to indicate “%”.
8. Read the % of duty cycle in the display.

7
DC CURRENT MEASUREMENTS
CAUTION: Do not make 10A current measurements 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 6000µA DC, set the function switch to the yellow µA
position and insert the red test lead banana plug into the µA/mA jack.
3. For current measurements up to 600mA DC, set the function switch to the yellow mA
position and insert the red test lead banana plug into the µA/mA jack.
4. For current measurements up to 10A DC, set the function switch to the yellow 10A/HZ/%
position and insert the red test lead banana plug into the 10A jack.
5. Press the MODE button to indicate “DC” on the display.
6. Remove power from the circuit under test, then open up the circuit at the point where you
wish to measure current.
7. 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.
8. Apply power to the circuit.
9. Read the current in the display.
AC CURRENT (FREQUENCY, DUTY CYCLE) MEASUREMENTS
CAUTION: Do not make 10A current measurements 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 6000µA AC, set the function switch to the yellow µA
position and insert the red test lead banana plug into the µA/mA jack.
3. For current measurements up to 600mA AC, set the function switch to the yellow mA
position and insert the red test lead banana plug into the µA/mA jack.
4. For current measurements up to 10A AC, set the function switch to the yellow 10A/HZ/%
position and insert the red test lead banana plug into the 10A jack.
5. Press the MODE button to indicate “AC” on the display.
6. Remove power from the circuit under test, then open up the circuit at the point where
you wish to measure current.
7. 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.
8. Apply power to the circuit.
9. Read the current in the display.
10. Press the Hz/% button to indicate “Hz”.
11. Read the frequency in the display.
12. Press the Hz/% button again to indicate “%”.
13. Read the % duty cycle in the display.
14. Press the Hz/% button to return to current measurement.

8
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 batteries and
unplug the line cords.
1. Set the function switch to the green ΩCAP position.
Insert the black test lead banana plug into the negative COM jack.
Insert the red test lead banana plug into the positive  jack.
2. Press the MODE button to indicate “"on the display.
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.
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 green Ω CAP position.
2. Insert the black lead banana plug into the negative COM jack.
Insert the red test lead banana plug into the positive  jack.
3. Press the MODE button to indicate” " and “Ω” on the display
4. Touch the test probe tips to the circuit or wire you wish to check.
5. If the resistance is less than approximately 50, the audible signal will sound. If the
circuit is open, the display will indicate “OL”.
DIODE TEST
1. Set the function switch to the green Ω CAP position.
2. Insert the black test lead banana plug into the negative COM jack and the red test lead
banana plug into the positive V jack.
3. Press the MODE button to indicate and V on the display.
4. Touch the test probes to the diode under test. Forward voltage will typically indicate 0.400
to 0.700V. Reverse voltage will indicate “OL”. Shorted devices will indicate near 0V and
an open device will indicate “OL” in both polarities.

9
TEMPERATURE MEASUREMENTS
1. Set the function switch to the green Temp position.
2. Insert the Temperature Probe into the input jacks, making sure to observe the correct
polarity.
3. Press the MODE button to indicate ºF or ºC
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 (about 30
seconds).
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.
CAPACITANCE MEASUREMENTS
WARNING: To avoid electric shock, disconnect power to the unit under test and discharge
all capacitors before taking any capacitance measurements. Remove the batteries and
unplug the line cords.
1. Set the rotary function switch to the green Ω CAP position.
2. Insert the black test lead banana plug into the negative COM jack.
Insert the red test lead banana plug into the positive V jack.
3. Press the MODE button to indicate “nF” on the display.
4. Touch the test leads to the capacitor to be tested.
5. The test may take up to 3 minutes or more for large capacitors to charge. Wait until the
readings settle before ending the test.
6. Read the capacitance value in the display
FREQUENCY/DUTY CYCLE MEASUREMENTS (ELECTRONIC)
1. Set the rotary function switch to the green “Hz %” position.
2. Press the Hz/% button to indicate “Hz” in the display.
3. Insert the black lead banana plug into the negative COM jack and the red test lead banana
plug into the positive Hz jack.
4. Touch the test probe tips to the circuit under test.
5. Read the frequency on the display.
6. Press the Hz/% button again to indicate “%” on the display.
7. Read the % of duty cycle on the display.

10
AUTORANGING/MANUAL RANGE SELECTION
When the meter is first turned on, it automatically goes into Autoranging. This automatically
selects the best range for the measurements being made and is generally the best mode
for most measurements. For measurement situations requiring that a range be manually
selected, perform the following:
1. Press the RANGE key. The “AUTO” display indicator will turn off.
2. Press the RANGE key to step through the available ranges until you select the range you
want.
3. To exit the Manual Ranging mode and return to Autoranging, press and hold the RANGE
key for 2 seconds.
Note: Manual ranging does not apply for the Capacitance and Frequency functions.
MAX/MIN
Note: When using the MAX/MIN function in Autoranging mode, the meter will “lock” into the
range that is displayed on the LCD when MAX/MIN is activated. If a MAX/Min reading
exceeds that range, an “OL” will be displayed. Select the desired range BEFORE
entering MAX/MIN mode.
1. Press the MAX/MIN key to activate the MAX/MIN recording mode. The display icon "MAX"
will appear. The meter will display and hold the maximum reading and will update only
when a new “max” occurs.
2. Press the MAX/MIN key again and the display icon "MIN" will appear. The meter will display
and hold the minimum reading and will update only when a new “min” occurs.
3. To exit MAX/MIN mode press and hold the MAX/MIN key for 2 seconds.
RELATIVE MODE
The relative measurement feature allows you to make measurements relative to a stored
reference value. A reference voltage, current, etc. can be stored and measurements
made in comparison to that value. The displayed value is the difference between the
reference value and the measured value.
1. Perform the measurement as described in the operating instructions.
2. Press the REL button to store the reading in the display and the "REL" indicator will
appear on the display.
3. The display will now indicate the difference between the stored value and the measured
value.
4. Press the REL button to exit the relative mode.
Note: The Relative function does not operate in the Frequency function.
DISPLAY BACKLIGHT
Press the HOLD key for >1 second to turn on or off the display backlight function.
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 30 minutes. To disable the auto power off
feature, hold down the MODE button and turn the meter on.
LOW BATTERY INDICATION
The icon will appear in the lower left conner of the display when the battery voltage
becomes low. Replace the battery when this appears.

11
Maintenance
WARNING: To avoid electric shock, disconnect the test leads from any source of voltage
before removing the back cover or the battery or fuse covers.
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 BATTERIES OF THE RECOMMENDED SIZE AND TYPE. Remove
old or weak batteries so they do not leak and damage the unit.
6. IF THE METER IS TO BE STORED FOR A LONG PERIOD OF TIME, the batteries should
be removed to prevent damage to the unit.
BATTERY INSTALLATION
WARNING: To avoid electric shock, disconnect the test leads from any source of voltage
before removing the battery cover.
1. Turn power off and disconnect the test leads from the meter.
2. Open the rear battery cover by removing the screw using a Phillips head screwdriver.
3. Insert the battery into battery holder, observing the correct polarity.
4. Put the battery cover back in place. Secure with the screw.
WARNING: To avoid electric shock, do not operate the meter until the battery cover is in
place and fastened securely.
NOTE: If your meter does not work properly, check the fuses and batteries to make sure that
they are still good and that they are properly inserted.
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 battery cover.
3. Gently remove the old fuse and install the new fuse into the holder.
4. Always use a fuse of the proper size and value (0.5A/1000V fast blow for the 600mA range
[SIBA 70-172-40], 10A/1000V fast blow for the 10A range [SIBA 50-199-06]).
5. 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.

12
Specifications
Function Range Resolutio
n
Accuracy
DC Voltage 600mV 0.1mV
(1.0% reading + 3 digits)
6V 0.001V
60V 0.01V
600V 0.1V
1000V 1V (1.0% reading + 5 digits)
AC Voltage 45Hz to 60Hz
6V 0.001V
(1.0% reading + 3 digits)
60V 0.01V
600V 0.1V
1000V 1V (1.5% reading + 5 digits)
All AC voltage ranges are specified from 5% of range to 100% of range
DC Current
600A 0.1A
(1.0% reading + 3 digits)
6000A 1A
60mA 0.01mA
600mA 0.1mA
6A 0.001A (1.5% reading + 3 digits)
10A 0.01A
(10A: 30 sec max with reduced accuracy)
AC Current 45Hz to 60Hz
600A 0.1A
(1.5% reading + 3 digits)
6000A 1A
60mA 0.01mA
600mA 0.1mA
6A 0.001A (2.0% reading + 5 digits)
10A
0.01A
(
1
0A: 30 sec max with reduced accuracy)
All AC voltage ranges are specified from 5% of range to 100% of range
NOTE: Accuracy is stated at 65oF to 83oF (18oC to 28oC) and less than 75% RH.

13
Function Range Resolution Accuracy
Resistance 600 0.1
(1.5% reading + 5 digits)
6k 0.001k
60k 0.01k
600k 0.1k
6M 0.001M
60M 0.01M (5.0% reading + 20 digits)
Capacitance 99.99nF* 0.01nF (4.5% reading + 20 digits)
999.9nF 0.1nF` (3.0% reading + 5 digits)
9.999F 0.001F
99.99F 0.01F
999.9F 0.1F
6000F 1F (5% reading + 5 digits)
Frequency
(electronic)
9.999Hz 0.001Hz
(1.0% reading + 5 digits)
99.99Hz 0.01Hz
999.9Hz 0.1Hz
9.999kHz 0.001kHz
99.99kHz 0.01kHz
999.9kHz 0.1kHz
9.999MHz 0.001MHz
10MHz 0.01MHz
Frequency
(electrical)
10.00-10KHz 0.01Hz (1.2% reading)
Sensitivity: 15Vrms
Duty Cycle 0.1 to 99.9% 0.1% (1.2% reading + 2 digits)
Pulse width: 100µs - 100ms, Frequency: 5Hz to 10kHz
Temp
(type-K)
-4 to 1400F 1F (3.0% reading + 5C /9F digits)
(probe accuracy not included)
-20 to 760C 1C
Note: Accuracy specifications consist of two elements:
*< 9.999nF(no specification)
 (% reading) – This is the accuracy of the measurement circuit.
 (+ digits) – This is the accuracy of the analog to digital converter.

14
Enclosure Double molded
Shock (Drop Test) 6.5 feet (2 meters)
Diode Test Test current of 1.5mA maximum, open circuit voltage 3V DC typical
Continuity Check Audible signal will sound if the resistance is less than 50 (approx.),
test current <0.35mA
Temperature Sensor Requires type K thermocouple
Input Impedance >10MΩ VDC & >10MΩ VAC
AC Response Averaging
ACV Bandwidth 50/60HZ(ALL WAVE) 45Hz to 1000Hz(SINE WAVE)
Crest Factor ≤3 at full scale up to 500V, decreasing linearly to ≤1.5 at 1000V
Display 6,000 counts
Overrange indication “OL” is displayed
Auto Power Off 30minutes (approximately) with disable feature
Polarity Automatic (no indication for positive); Minus (-) sign for negative
Measurement Rate 3 times per second, nominal
Low Battery Indication “ ” is displayed if battery voltage drops below operating
voltage
Battery 1.5VAAA *4 battery
Fuses mA, µA ranges; 0.8A/1000V ceramic fast blow
A range; 10A/1000V ceramic fast blow
Operating Temperature 41F to 104F (5C to 40C)
Storage Temperature -4F to 140F (-20C to 60C)
Operating Humidity Max 80% up to 87F (31C) decreasing linearly to 50% at 104F
(40C)
Storage Humidity <80%
Operating Altitude 7000ft. (2000meters) maximum.
Weight 0.753lb (342g) (includes holster).
Size (182x 82 x 59mm) (includes holster)
Safety This
meter is intended for origin of installation use and protected, against the users, by double
insulation per EN61010-1 and IEC61010-1 2nd Edition (2001) to Category IV 600V and
Category III 1000V; Pollution Degree 2. The meter also meets UL 61010-1, 2nd Edition
(2004), CAN/CSA C22.2 No. 61010-1 2nd Edition (2004), and UL 61010-2-033, 1st Edition
(2012)