Clarke CDM 25 User manual

CDM25 - Page 1
DIGITAL
MULTIMETER
Model No: CDM 25
OPERATING
INSTRUCTIONS
0507

CDM25 - Page 2
Thank you for purchasing this CLARKE compact digital
multimeter.
This instrument is designed to measure AC and DC
voltages, AC and DC current, Resistance, Diode, and
to perform continuity checks with accuracy and ease.
GUARANTEE
This product is guaranteed against faults in manufacture
for 12 months from purchase date. Keep your receipt
as proof of purchase. This guarantee is invalid if the
product has been abused or tampered with in any way,
or not used for the purpose for which it is intended. The
reason for return must be clearly stated. This guarantee
does not affect your statutory rights.
FEATURES
•Automatic Power OFF.
•DC / AC Voltage measurement 1mV to 600V
•DC /AC Current measurement 0.01mA to 400mA
•Full overload protection
•Fully auto-Ranging
•Resistance measurement 0.1Ωto 40 MΩ
•Data Hold function
•Audible continuity function
•Diode test at 25µA test current
•3.75 LCD Display
•Auto polarity indication

CDM25 - Page 3
SPECIFICATIONS
Measuring Method: Dual integration mode
Sampling Rate: 2 - 3 times per second
Low Battery Indication: BATT displayed on the left of LCD
Operating Temperature: 0EC - 40EC, less than 80% RH
Dimensions: 70 (W) x 120 (H) x 18 (D) mm
Weight Approx: 110g (Incl batteries)
Battery: 3V, SR44 x 2 or equivalent.
Accessories: Carrying case, Fuse, Operating
Instruction booklet
TABLE OF CONTENTS
Features ....................................................................... 2
Safety Precautions ..................................................... 4
Description of Front Panel ........................................ 5
Operating Instructions .............................................. 6
DC Voltage ................................................................. 6
AC Voltage ................................................................. 7
DC Current .................................................................. 8
AC Current .................................................................. 8
Resistance Measurement ......................................... 9
Diode ........................................................................... 10
Audible Continuity Test ............................................. 10
Dta Hold Function ...................................................... 10
Maintenance .............................................................. 11
Battery Replacement ................................................ 11
Fuse Replacement ..................................................... 11
Replacement Parts .................................................... 11
When disposing of this product, do not dispose of with general
waste. It must be disposed of according to the laws governing
Waste Electrical and Electronic equipment, at a recognised
disposal facility.

CDM25 - Page 4
SAFETY PRECAUTIONS
Read this information before using the meter, taking special care
regarding any WARNING or IMPORTANT notices. The following safe
practices and proper operating procedures should be followed when
using any multimeter:
•WARNING: TO AVOID ELECTRIC SHOCK, USE CAUTION WHEN
WORKING ABOVE 40V DC OR 25V AC RMS. SUCH VOLTAGES POSE
A SHOCK HAZARD
• Inspect the test leads for insulation damage or exposed metal.
Damaged leads should be replaced.
• Select the proper function and range for your measurement.
• Avoid severe shocks and do not drop the multimeter.
• Do not allow the meter to be used if it is damaged or if its safety is
impaired.
• Electrically disconnect the live, or hot, test lead before
disconnecting the common test lead.
• Follow all equipment safety procedures. Disconnect the input
power and discharge all high-voltage capacitors through a
protective impedance before testing in Ωand with the
multimeter.
• Avoid working alone.
• When making a current measurement, turn the power off before
connecting the multimeter in the circuit. Overloading a current
shunt will cause excessive heat.
• When measuring transformer secondary or motor winding current,
check the multimeter fuses first.
• When testing circuits take extra care not to touch any bare metal
including the ends of the test probes.
• The use of makeshift fuses and the short-circuiting of fuse holders is
prohibited.
• Whenever it is likely that the protection has been impaired, the
meter shall be made inoperative and be secured against any
unintended operation.
• Never attempt to measure a voltage or current higher than the
maximum rating of the meter.

CDM25 - Page 5
DESCRIPTION OF PANEL
1 - Push Button ON/OFF switch
2 - D - H Push Button for data hold function
3 - Rotary Function Switch
4 - Test Leads. Red - positive, Black - negative polarity
5 - 3 ¾ digit LCD from 0 to 9999 counts
3
4
2
1
5

CDM25 - Page 6
OPERATING INSTRUCTIONS
WARNING: Extreme care should be taken when reading
high voltages. DO NOT exceed maximum voltage for
which the meter is designed.
DC VOLTAGE MEASUREMENT
1. Set function switch to V position
2. Set range switch to desired position. If magnitude
of voltage is unknown beforehand, set the switch
to its highest range and then reduce until
satisfactory reading is obtained.
3. Connect test leads across the source or load under
measurement. The polarity of the RED lead
connection will be indicated as well as the voltage.
4V 1mV ± 0.5% of rdg ± 2 digits
40V 10mV
400V 0.1V ± 0.8% of rdg ± 2 digits
600V 1V
Maximum allowable input: 600V DC
Input Impedance: 10MÙ
Accuracy
(1 year 18EC 28EC)
Range Resolution

CDM25 - Page 7
AC VOLTAGE MEASUREMENT
1. Set function switch to V position.
2. Set range switch to desired position. Measurement
reading can be obtained at 2V and 20V positions,
but accuracy is not guaranteed.
3. Connect test leads across load or source under
measurement. Read voltage value on display.
~
4V 1mV ±0.8% of reading ± 5%
40V 10mV
400V 0.1V ± 0.5% of full scale ± 2 digits
600V 1V
Frequency Range: 50 - 400Hz. 50 - 60 Hz
for 400/600V ranges.
Max. Allawable Input: 600V rms AC
Accuracy
(1 year 18EC 28EC)
Range Resolution

CDM25 - Page 8
DC CURRENT
1. Set function switch to A position
2. Open the circuit to be measured and connect the
test leads in series with the load in which current is to
be measured.
3. Read current value on display along with polarity of
RED test lead.
Accuracy
(1 year 18EC 28EC)
Range Resolution
40mA 0.01mA
400mA 0.1mA
Overload Protection: 0.5A/250V fuse.
± 2.0% of rdg ± 2 digits
AC CURRENT
1. Set function switch to A position
2. Open the circuit to be measured and connect the
test leads in series with the load in which current is to
be measured.
3. Read current value on display along with polarity of
RED test lead.
Accuracy
(1 year 18EC 28EC)
Range Resolution
40mA 0.01mA
400mA 0.1mA
Overload Protection: 0.5A/250V fuse.
± 2.0% of rdg ± 2 digits
~

CDM25 - Page 9
RESISTANCE MEASUREMENT
WARNING: If resistor to be measured is connected to
a circuit, ensure all power to the circuit is OFF, and all
capacitors are fully discharged before attaching test
leads.
1. Set function switch to Ωposition.
2. Connect test leads across resistor to be measured,
and read resistance value on display.
400W 0.1W
4kW 1W
40kW 10W
400kW 100 kW
4MW 1KW
40MW 10KW
Maximum Open Circuit Voltage: 0.65V
Overload Protection: 250V rms AC
Accuracy
(1 year 18EC 28EC)
Range Resolution
±1.5% of rdg ± 2 digits
±3.0% of rdg ± 2 digits

CDM25 - Page 10
DIODE TEST
1. Set function switch to position.
2. Connect the red lead to the anode of the diode to be
tested, and the black lead to the cathode. Read the
approx. forward voltage drop on the display in mV. If
the leads are reversed, “OL” will be displayed.
AUDIBLE CONTINUITY TEST
1. Set function switch to .))) position.
2. Connect the test leads to two points of a circuit. The
buzzer will sound if the resistance is lower than 50 ohms.
Resolution Description
0.1 ohm Built in buzzer sounds when
resistance is less than 50 ohms
Overload Protection: 250V rms AC
Resolution Test Current (Max) Open Circuit Voltage
1mV 25µV 3.0V
Overload Protection: 250V rms AC
DATA HOLD FUNCTION
D-H button is used to hold a measuring result. When
this button is pushed, the last reading will be held on
the LCD until the button is pushed again, or the
function switch is reset.

CDM25 - Page 11
MAINTENANCE
CAUTION:
1. Make sure test leads are dsconnected from the
test drcuit, and range switch is set to OFF before
opening the case.
2. Do not operate the instrument unless the back
cover is in place and fastened.
BATTERY REPLACEMENT
1. When batteries become exhausted, or drop below the
operating voltage, “BATT” sign will appear on the LCD.
2. Turn off meter and remove test leads from dl test
circuits pnor to replacing batteries.
3. Remove the screw from the back cover and open
the case. Replace batteries, ensuring proper
polarity is observed.
REPLACEMENT OF FUSE
Proceed as for changing battery, ensuring the fuse
replacement is of the same size and rating as the original.
Fculure to do so may result in serious damage to your
meter or possibly even fire.
(Fuse must be no more than 0.5A/250V)
REPLACEMENT PARTS
1. Test Leads (pair) Part No. CHI5O1
2. Fuse (0.5A1250V) Part No. CH1502

CDM25 - Page 12
For Spare Parts and Service, please contact your nearest dealer,
or CLARKE International, on one of the following numbers.
PARTS & SERVICE TEL: [phone]
PARTS & SERVICE FAX: [phone]
or e-mail as follows:
PARTS: [email protected]
SERVICE: [email protected]
Other Clarke quality products include:
• AIR COMPRESSORS
• WELDERS
• POWER WASHERS
• GENERATORS
• BATTERY CHARGERS/BOOSTERS
• ENGINE CRANES
• WOOD & METAL LATHES
• SANDERS
• BANDSAWS/TABLE SAWS
• AND MUCH MUCH MORE
PARTS & SERVICE
For spare parts and servicing, please contact your
nearest dealer, or Clarke International on one of
the following numbers: