ElencoTMElectronics, Inc.
150 W. Carpenter Avenue
Wheeling, IL 60090
(847) 541-3800
http://www.elenco.com
e-mail: elenco@elenco.com
OPERATOR’S
INSTRUCTION MANUAL
M-2785
WIDE MEASURING
DIGITAL MULTIMETER
with 15MHz Max. Frequency
Measurement
Copyright © 2003 ElencoTMElectronics, Inc.
Contents
1. Safety Information 3
2. Introduction 4
3. Features 5
4. Specifications 5
4-1 General Specifications 5
4-2 Measurement Specifications 6
5. Operation 8
5-1 Preparation and Caution before Measurement 8
5-2 Front Panel Description 8
5-3 How to Make Measurements 10
6. Maintenance 12
6-1 Battery Replacement 13
6-2 Fuse Replacement 13
6-3 Calibration Procedure 14
7. Using the Stand 15
-2-
7. Using the Tilt Stand
Use the tilt stand on the back side to prop up the meter or to
hold the test leads.
Propping up the Meter
This meter has the tilt-stand on the back side to help provide a
better viewing angle.
To use the tilt-stand, just open it away from the meter and set
it on a flat surface.
Holding the Test Leads
The tilt-stand equips the two holes at the center to hold the test
leads while you are not doing any measurements.
Simply set each red & black lead in each hole.
-15-
! WARNING !
PLEASE READ THIS INSTRUCTION MANUAL
CAREFULLY
Misuse and/or abuse of this instruction cannot be prevented by
any printed word and may cause injury and/or equipment
damage.
Please follow all these instructions and measurement
procedures faithfully, and adhere to all standard industrial
safety rules and practices.
The multimeter shall be used in over voltage category II !
CAUTION
Do not attempt to measure a voltage while the test leads are
plugged into the current input terminals.
This would place a short circuit across the voltage since
current ranges have a low impedance. Always check the
position of the test leads before making measurements.
5. Remove the fuse from the holder and replace it with a new fuse of
the same specified value.
6. Close the bottom case and secure with screws.
7. Replace the meter into the holster.
6-3. Calibration Procedures
Adjustment should be done with a highly accurate
standard.
(Better than 0.1% accuracy).
1. Remove the meter from the holster.
2. Remove the two screws on the battery cover, then
detach it from the bottom case.
3. Remove the two screws on the bottom case and
detach it from the top case.
4. With the meter operating, set the function/rotary switch to the
200mV DC range (20mF for capacitance), and apply 190mV DC
(10mF for capacitance) from an accurate source. With a small
screwdriver inserted into the semi-variable resistor SVR1 (SVR2
for capacitance), carefully turn it until the reading obtains 190mV
(10mF for capacitance).
NOTE: Be sure to finish the basic calibration in the DCV range first
before calibrating the Capacitance Range.
-14-
1. Safety Information
To ensure that the meter is used safely, follow all of the safety and
operation instructions in this manual. If the meter is not used as
described in the manual, the safety features of the meter might be
impaired.
•
Do not use the meter if the meter or the test leads look damaged,
or if you suspect that the meter is not operating properly.
• Turn off the power to the circuit under test before cutting,
unsoldering, or breaking the circuit. Small amounts of current
can be dangerous.
• Use caution when working above 60VDC or 30VAC rms. Such
voltages pose a shock hazard.
• When using the test lead, keep your fingers behind the guards
on the test lead.
• Disconnect the live test lead before disconnecting the common
test lead.
• To avoid damage to the meter, do not exceed the input limits
shown below.
• This digital multimeter is designed for indoor use only.
• This digital multimeter has a measuring deviation of 2.3% by
immunity test according to EN50082-1.
-3-
WARNING
Use only an equivalent fuse to the one specified. Use of an incorrect fuse
could result in a serious injury or meter damage.
WARNING
To avoid the risk of electric shock, always unplug components from the
transistor test socket and capacitor test socket before using the meter to
measure voltage or current. These sockets are not isolated from the meter
circuitry.
FUNCTION INPUT JACK INPUT LIMITS
VDC
V/W/Hz & COM
1000VDC
VAC 750VAC rms
W.Hz
V/W/Hz & COM 500V rms
mA, mA DC/AC mA & COM 200mA DC/AC
10A DC/AC 10A & COM 10A DC/AC
FCx
h
FE
PNP/NPN
Remove
Safety Symbols
This marking adjacent to another marking, terminal, or
operating device indicates that the operator must refer to
the explanation in the operating instructions to avoid
damage to the equipment and/or to avoid personal injury.
This WARNING sign denotes a hazard. It calls attention to
a procedure, practice or the like, which if not correctly
performed or adhered to, could result in personal injury.
This CAUTION sign denotes a hazard. It calls attention to
a procedure, practice or the like, which, if not correctly
adhered to, could result in damage to or destruction of part
or all of the instrument.
This marking 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) 500 volts.
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 instrument and its test leads
should not be handled when these terminals are
energized.
This marking indicates that equipment is protected
completely be the double insulation.
2. Introduction
This meter is a 3 1/2 digit digital multimeter that is rugged, reliable
and convenient to use, while providing all of the accuracy and
features needed for any application. It performs DC/AC voltage,
DC/AC current, resistance, transistor, TTL/CMOS logic test,
capacitance, frequency, diode, continuity measurement, combined
with Data and Peak Hold, and Auto Power Off.
It is designed for the professional at work in the field or in the
laboratory, even hobby and home application.
-4-
6-1. Battery Replacement
Replace the battery when “ ” appears on the display.
1. Remove the meter from the holster.
2. Remove the two screws on the battery cover. Then, detach it from
the bottom case.
3. Unsnap the battery from the connector, and replace it with a new 9
volt battery.
4. Wind the excess lead length around the battery clip, and install the
battery.
5. Close the battery cover and secure it with the screws.
6. Replace the meter into the holster.
6-2. Fuse Replacement
This meter is provided with a 0.5A/250V and a 10A/250V fuses to
protect the current measuring circuits which measure up to 200mA
and 10A.
1. Turn off the power.
2. Remove the meter from the holster.
3. Remove the screws on the battery cover.
4. Detach the battery cover from the bottom case.
-13-
!
WARNING
CAUTION
500V max.
+
CAUTION
Failure to turn off the DMM before installing the battery could
result in damage to the meter if the battery is connected to the
battery terminal incorrectly.
(9) Data Hold
1. This function enables the user to “freeze” a measurement reading and
then remove the test leads while the reading remains displayed on the
LCD. DATA-H is useful when it is necessary to pay very close attention
to your work. Freeze the display by depressing the DATA-H switch.
Pushing the DATA-H switch again releases the display.
(10) Auto Power Off
This meter will be shut off automatically after 30 minutes that the meter has
not been used without a change of the range or function switch.
This function helps in conserving battery life.
To turn the meter back on, simply press the DATA-H switch twice.
(11) Logic (TTL/CMOS) Test
1. Set function/rotary switch to desired “TTL or CMOS” position.
2. Plug the red test lead into the “V.W.Hz” jack and the test lead tip to the
point to be tested.
3. Plug the black test lead into the “COM” input jack and the test lead tip to
the common bus of the logic circuitry to be measured.
4. With a logic high pulse (1), the indicator will display on the LCD. With
a logic low pulse (0) the indicator will appear on the LCD.
(12) Peak
1. This function enables the user to “freeze” a peak (maximum)
measurement reading. The peak function will work by pressing the
PEAK-H switch. Pushing this switch again releases the display.
6. Maintenance
-12-
3. Features
• 10 Functions / 45 Measuring Ranges
• Surface Mounted PC Board Assembly
• 1% Basic Accuracy
• 10MW Input Impedance
• Large LCD with Function/Range Annunciator
• Full Overload Protection
• Peak Hold
• Data Hold
• Auto Power Off
• Auto-Range Selected Frequency Measurement up to Max. 15MHz reading
• Double-insulated Safety Input Jack
• Tilt Stand with Test Lead Holder Equipped
• Easy Two Changes of Fuses & Battery by Divided Battery Cover
• Holster
• Low Battery Indicator
4. Specifications
4-1. General Specifications
Display 3 1/2 LCD 0.71” height, max. reading of 1999
with annunciators.
Polarity Automatic “ ” is displayed.
Overrange Indication “OL” on LCD is displayed.
Low Battery Indication “ ” sign on LCD readout.
Auto Power Off Approximately 30 minutes.
Operation Temperature 0
O
C to 50OC
less than 80% relative humidity up to 35OC
less than 70% relative humidity from 35OC to 50OC.
Storage Temperature -15OC to 50OC
Temperature Coefficient 0OC to 18OC and 28OC to 50OC
less than 0.1 X applicable accuracy
specification per OC.
Power 9V Alkaline or Carbon Zinc battery
(NEDA 1604)
Battery Life (typical) 100 hours with carbon zinc cells
200 hours with alkaline cells
Dimensions 3.54” (W) x 7.48” (L) x 1.37” (H) (w/o holster)
Weight Approximately 0.75 lb. (w/o holster)
Accessories Safety Test Leads - 1 pair
Operator’s Manual - 1 pc.
Holster - 1 pc.
-5-
WARNING
Before attempting battery & fuse removal or replacement, disconnect
the test leads from any energized circuits to avoid hazard.
+
4-2. Measurement Specifications
Accuracy of specifications apply for 1 year after purchase when
operated in a temperature of 18OC to 28OC (64OF to 82OF) and a
relative humidity of less than 75%.
Basic electrical specifications are given as +
[(% of reading) +
(number of least significant digits)].
DC Voltage
200mV 100mV+(0.25% of rdg+2dgt)
2V 1mV +
(0.8% of rdg+2dgt)
20V 10mV +(0.8% of rdg+2dgt) DC 1000V
200V 100mV +
(0.8% of rdg+2dgt) or PEAK AC
1000V 1V +(0.8% of rdg+2dgt)
NORMAL MODE REJECTION RATIO: greater than 46dB at 50Hz, 60Hz (1k unbalance)
Overload Protection: 1100VDC or peak AC for 50 seconds.
AC Voltage
200mV 100mV+(1.0% of rdg+4dgt)
2V 1mV +
(1.0% of rdg+4dgt)
20V 10mV +(1.0% of rdg+4dgt)
AC 750V max.
200V 100mV +(1.0% of rdg+4dgt) 50Hz - 400Hz
750V 1V +
(1.5% of rdg+5dgt)
Resistance
200W 0.1W +(0.8% of rdg+4dgt)
2kW 1W +
(0.8% of rdg+4dgt)
20kW 10W +
(0.8% of rdg+4dgt) Protected by
200kW 100W +
(0.8% of rdg+4dgt) PTC
2MW 1kW +
(1.5% of rdg+5dgt) (500V rms)
20MW 10kW +
(2.0% of rdg+10dgt)
200MW 100kW +
(2.0% of rdg+10dgt)
DC Current
20mA 10nA +(0.8% of rdg+4dgt)
200mA 100nA +
(0.8% of rdg+4dgt)
2mA 1mA+
(0.8% of rdg+4dgt)
Protected by
20mA 10mA+
(0.8% of rdg+4dgt)
0.5A/250V
200mA 100mA+
(1.0% of rdg+3dgt)
Fuse
10A 10mA +
(1.5% of rdg+3dgt) 10A/250V Fuse
Maximum Measuring Voltage Drop: Less than 300mV.
-6-
(4) Diode Test
1. Plug the red test lead into the “V/W/Hz” input jack and the black one into
the “COM” input jack.
2. Set the function rotary switch to position.
3. If the semiconductor junction being measured is connected to a circuit,
turn off the power to the circuit being tested and discharge all capacitors.
4. Connect the test leads to the device and read the forward value on the
digital display.
5.
If the digital display reads overrange (OL), reverse the lead connections.
The placement of the test leads when the forward reading is displayed
indicates the orientation of the diode.
The red lead is positive and the black lead is negative. If overrange (OL)
is displayed with both lead connections, the junction is open.
(5) Transistor hFE Measurement
1. Transistor must be out of circuit.
2. Set the function/rotary switch to the hFE position.
3.
Plug the emitter, base and collector leads of the transistor into the correct
holes in either the NPN or the PNP transistor test socket, whichever is
appropriate for the transistor you are checking.
4. Read the hFE (beta or DC current gain) in the display.
(6) Capacitance Measurement
1. Set the function/rotary switch to the desired capacitance position.
2. Discharge capacitor before measurement.
3. Insert the capacitor leads into the capacitor test socket.
4. One lead must be inserted into one hole and the other lead must be
inserted into the other hole.
5. Read the capacitor value on the digital display.
(7) Continuity Test
1. Plug the red test lead into the “V/W/Hz” input jack and the black one into
the “COM” input jack.
2. Set the function/rotary switch to position.
3. Buzzer sounds if the resistance between two leads is less than approx.
30W.
(8) Frequency Measurement
1. Plug the red test lead into the “V.W.Hz” input jack and the black one into
the “COM” input jack.
2. Set the function/rotary switch to the “Hz” position.
3. Connect the test leads to the frequency source to be measured.
4. Read the frequency value on the digital display.
-11-
Range Resolution Accuracy Maximum Input
Range Resolution Accuracy Maximum Input
Range Resolution Accuracy Input Protection
Range Resolution Accuracy Input Protection
5-3. How to Make a Measurement
(1) DC/AC Voltage Measurement
1.
Set the desired voltage type (DC or AC) by pushing the switch marked DC/AC.
2. Plug the red test lead into the “V.W.Hz” input jack and the black one into
the “COM” input jack.
3. Set the function/rotary switch to the desired “V” position. If the magnitude
of the voltage is not known, set the function/rotary switch to the highest
range and reduce until a satisfactory reading is obtained.
4. Connect the test leads to the device or circuit being measured.
5. Turn on the power to the device or circuit being measured. Voltage value
will appear on the digital display along with voltage polarity.
6. Turn off the power to the device or circuit being tested and disconnect the
test leads.
NOTE: When the switch is set to AC Voltage ranges, some residual voltage value might
be displayed on the LCD readout, but it doesn’t influence the actual measurement result.
(2) DC/AC Current Measurement
1.
Set the desired voltage type (DC or AC) by pushing the switch marked DC/AC.
2. Plug the red test lead into the “mA” input jack for current measurement up
to 200mA, and the black one into the “COM” input jack.
3. Set the function/rotary switch to the desired “A” position. If the magnitude
of the current is not known, set the function/rotary switch to the highest
range and reduce until a satisfactory reading is obtained.
4. Open the circuit to be measured, and connect the test leads in series with
the load in which current is to be measured.
5. Read current value on the digital display.
6.
Turn off all power to the circuit being tested and disconnect the test leads.
7. To measure in the 10A range, use the “10A” jack as the input jack.
NOTE: BE SURE TO MEASURE WITHIN 30 SECONDS TO AVOID HIGH
CURRENT HAZARD.
(3) Resistance Measurement
1. Plug the red test lead into the “V.W.Hz” input jack and the black one into
the “COM” input jack.
2. Set the function/rotary switch to the desired “W” position.
3. If the resistance being measured is connected to a circuit, turn off the
power to the circuit being tested and discharge all of the capacitors.
4. Connect the test leads to the circuit being measured.
When measuring high resistance, be sure not to contact adjacent points,
even if insulated, because some insulators have a relatively low insulation
resistance, causing the measured resistance to be lower than the actual
resistance.
5. Read resistance value on the digital display.
NOTE: Test lead resistance can interfere when measuring low resistance readings and
should be subtracted from the resistance measurement for accuracy. Select 200
W
resistance range and make a firm contact between the two test lead points (short them
together). The display value is the test lead resistance to be subtracted.
-10-
AC Current
20mA 10nA +(1.2% of rdg+3dgt)
200mA 100nA +
(1.2% of rdg+3dgt) Protected by
2mA 1mA+
(1.2% of rdg+3dgt) 0.5A/250V
20mA 10mA+
(1.2% of rdg+3dgt) Fuse
200mA 100mA+
(1.5% of rdg+3dgt)
10A 10mA +
(2.0% of rdg+5dgt) 10A / 250V Fuse
Maximum Measuring Voltage Drop: Less than 300mV.
Frequency
2kHz 1Hz +(0.25% of rdg+2dgt) Maximum Input
20kHz 10Hz +(0.25% of rdg+2dgt) Level: 500V rms
200kHz 100Hz +
(0.25% of rdg+2dgt)
2MHz 1kHz +(0.25% of rdg+2dgt)
15MHz 10kHz +(0.25% of rdg+2dgt)
Input Sensitivity: 2kHz to 2MHz - 200mV rms (TTL only)
15MHz - 500mV rms (TTL only)
Min. Pulse Width: <25ns
Capacitance
2nF 1pF +(3.0% of rdg+3dgt)
Test Frequency 400Hz +3.0%
20nF 10pF +(3.0% of rdg+3dgt) Test Voltage 120mV
200nF 100pF +(3.0% of rdg+3dgt)
2mF 1nF +(3.0% of rdg+3dgt)
20mF 10nF +
(3.0% of rdg+3dgt)
200mF 100nF +
(3.0% of rdg+3dgt)
TR hFE
NPN 10mA DC @3.0V DC
PNP 10mA DC @3.0V DC
Continuity Test
30W 2.5kHz < 100ms
DIODE TEST
Measures forward resistance of a semiconductor junction in kW at max. test current of
1.5mA.
-7-
Range Resolution Accuracy Input Protection
Range Resolution Accuracy Input Level
Range Resolution Accuracy
Test Voltage & Frequency
Range Test Condition Test Voltage
Range Threshold
Continuity Beeper
Response Time
5. Operation
5-1. Preparation and Caution Before Measurement
1. The function switch should be set to the range to be measured
before operation.
If the function must be switched during a measurement, always
remove the test leads from the circuit being measured.
2. If the unit is used near noise-generating equipment, be aware
that the display may become unstable or indicate large errors.
3. Avoid using the unit in places with rapid temperature variations.
4. In order to prevent damage or injury to the unit, never fail to keep
the maximum tolerable voltage and current, especially for the
10A current range.
5. Carefully inspect the test leads. If damaged, discard and
replace.
6. In order to avoid wrong range selection, be sure to check the
annunciator on the display.
5-2. Front Panel Description
1. Liquid Crystal Display
2. DC/AC Selector Switch
3. Data Hold Switch
4. Function/Rotary Switch
5. Capacitor Test Socket
6. TR hFE Test Socket
7. 10A Input Jack
8. mA Input Jack
9. Common Input Jack
10. V.W.Hz Input Jack
11. Holster
12. Peak Hold Switch
-8-
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