CD770
DIGITAL MULTIMETER

INSTRUCTION MANUALTable of Contents【1】SAFETY PRECAUTIONS – Before use, read the following safety precautions.1-1 Explanation of Warning Symbols
001
001
1-2 Warning Messages for Safe Use
1-3 Overload Protection
002【2】APPLICATIONS AND FEATURES
003
2-1 Applications003
2-2 Features【3】NAMES OF COMPONENT UNITS
004
3-1 Meter004
3-2 Test Leads
3-3 Display005【4】DESCRIPTION OF FUNCTIONS
006
4-1 Power Switch & Function Switch
006
4-2 Measuring Function Selection:
4-3 Data Hold:006
006
4-4 Range Hold:
4-5 Relative Measurement:
007
4-6 Auto Power Off
007
007
4-7 Battery Low Warning Indication【5】MEASURING PROCEDURE
008
5-1 Start-up Inspection
5-2 Voltage Measurement ( )010
5-3 Resistance Measurement ( ), Diode Test ( ),011
Continuity Check ( )5-4 Frequency Measurement ( )012013
5-5 Capacitance Measurement ( )/)014
5-6 Current Measurement (【6】MAINTENANCE
016
6-1 Maintenance and Inspection
016
6-2 Calibration and Inspection
6-3 Storage
016
6-4 Battery and Fuse Replacement016【7】After-Sale Service
018
7-1 Warranty and Provision018
7-2 Repair019
7-3 SANWA web site
【8】SPECIFICATIONS
020
8-1 General Specifications
021
8-2 Measuring Range and Accuracy

Before use, please read this manual thoroughly to ensure correctand safe use. After reading it, keep it together with the productfor reference to it when necessary. Using this product in ways not
specified in this manual may damage its protection function. The
instructions given under the headings of “
WARNING” and “
CAUTION” must be followed to prevent accidental burn and electric
shock.

5. Never use the meter near equipment which generates strong
electromagnetic waves or is charged.
6. Never use the meter if the meter or test leads are damaged or broken.
7. Never use the meter with the case or battery lid removed.
8. Be sure to use the fuse of the speciﬁed rating and speciﬁcation.
9. During measurement, do not hold the test pin side of theﬂange of the test leads.
10. To start measurement, ﬁrst connect the ground side (black test lead).
When disconnecting, the ground side must be disconnected last.
11. During measurement, do not change the meter to anotherfunction or range nor replace the plugs to other terminals.
12. Before starting measurement, make sure that the function andrange are properly set.
13. Never use the meter when it is wet or with wet hands.
14. Be sure to use the speciﬁed type of test leads.
15. Never attempt repair or modification, except for battery andfuse replacement.
16. Inspect the meter at least once a year.
17. This meter is for indoor use only.

CAUTION

1. Correct measurement may not be performed when using themeter in the ferromagnetic / intense electric field such as places
near a transformer, a high-current circuit, and a radio.
2. The meter may malfunction or correct measurement may not be
performed when measuring special waveform such as that of theinverter circuit.

1-3 Overload Protection
The maximum rated input value and overload protection havebeen established for the input terminals of each function.
Function

V Hz

Input Terminal Max. Rated Input Value Max. Overload Protection Input Value
and

and

DC･AC 600 V
DC･AC 600 V
Do not input avoltage or current.
DC･AC 400 μA
Do not input a voltage .
0.5 A/250 V fuse
DC･AC 400 mA Breaking capacity 1.5 kA
Do not input a voltage .

— 2 —[2] APPLICATIONS AND FEATURES
2-1 Applications
This is a digital multimeter designed for measurement of lowvoltage circuits. This meter is useful for measuring / analyzing
circuits of small communication devices, home electric appliances andbatteries.
2-2 Features• The current terminal is protected with a safety cap.
• Easy-to-read display showing Eye-friendly large size LCD.
• Frequency measurement and capacitance measurement
functions provided.
• Easy-to-hold design.
• Test probes can be held on the body.
• Double molding with outside made of elastic elastomer material.

— 3 —[3] NAMES OF COMPONENT UNITS
3-1 Meter
LCD

Select button

Range holdbuttonRelative button

Data hold button

Power switch &function switch

Safety cap

Measuring terminal

μA/mA

COM (common)
terminal

Measuringterminal

3-2 Test Leads

21

— 4 —

3-2 Display

Indication of numerical value.
Indication of relative mode operation.
Indication of negative sign ofnumerical data.
Indication of AC measuring function
operation.
Indication of DC measuring function
operation.
Indication of auto range mode operation.
Not used with this meter.
Indication of diode test function operation.
Indication of continuity check function
operation.
Indication of data hold mode operation.
Indication of relative mode operation.
Indication of battery low warning.
Indication of units of measurement.

— 5 —[4] DESCRIPTION OF FUNCTIONS
4-1 Power Switch & Function Switch
Turn this switch to turn on and off the power and select ameasuring function.
4-2 Measuring Function Selection:
When thebutton is pressed, the functions change asfollows:
AC voltage ( )DC voltage ( )• V position: DC voltage ( )• / / position: Resistance measurement ( )diode test ( )continuity check ( )resistance measurement ( )DC current ( )• µA position: DC current ( ) AC current ( )• mA position: DC current ( )AC current ( )DC current ( )4-3 Data Hold:
When thebutton is pressed, the value indicated will beheld. (“ ” will appear on the display.) The indicated value will notchange if the measurement input fluctuates.
When this button is pressed again, the hold status will becanceled and the meter will return to the measurement mode.
(“ ” will disappear from the display.)
Remarks:
The DATA HOLD button does not work with thefunction.
4-4 Range Hold:
When thebutton is pressed, the meter will be set in the
manual mode and the range will be fixed. (“” will disappear
from the display.) In the manual mode, each time this button ispressed, the range changes. While checking the unit and decimal
point on the display, select the best range.
To return to the auto range, hold this button pressed for 1 secondor longer. (“” will appear on the display.)
Remarks:
The RANGE HOLD button does not work with the ( ), ( ),( ) and ( ) functions.
— 6 —4-5 Relative Measurement:
When thebutton is pressed,
andwill light and the
input value when the button was pressed will become 0 as thereference. To cancel it, press the button again.
Example: Display after pressing the button at DC 30.00 V input
Actual Input Value
DC 30.00 V
DC 35.00 V
DC 25.00 V

Value in Display
DC 0.00 V
DC 5.00 V
DC -5.00 V

Remarks:
This mode cannot be used with thefunction. When a function
other than () is used, the range is fixed during relative
measurement.
4-6 Auto Power Off
If no switch or button is operated for Approx. 30 minutes after
power on, the power will automatically be turned off and thedisplay will become blank.
To reset the meter, press any button or remove the object tomeasure from the DMM and set the function switch to OFF. Set
the function switch again according to the measurement andconnect the object to measure.
To cancel this function, turn on the power of meter while holding
thebutton pressed.
4-7 Battery Low Warning Indication
When the built-in batteries have been discharged and the voltage
has dropped to below Approx. 2.4 V, “ ” mark will appear in thedisplay. When this mark flickers or lights, replace both twobatteries with new ones.

— 7 —[5] MEASURING PROCEDUREWARNING

1. Do not apply an input signal exceeding the maximum rated
input of each function.
2. During measurement, do not change the function switch.
3. During measurement, do not touch the test pin side of theflange of the test lead.
4. When measurement has been finished, remove the test pinsfrom the object measured and return the function switch to the
OFF position.
5-1 Start-up Inspection

CAUTION

1. Be sure that the battery low warning mark is not flickering or lit, whenthe meter is turned on. If it is flickering or lit, replace the batteries withnew ones.
2. Do not use the meter if the meter or test lead is damaged or broken.
3. Make sure the test leads are not cut and the fuse has not blown.

— 8 —Always conduct the start-up inspection to ensure safety. (Inspection
by the continuity check.)
Inspection start
Meter ortest leads
not broken?

Broken.
Check

Not broken.
Insert black plug of test lead toterminal and red plug to() terminal.
Set with function switch andselect button.
Short red and black test pins.

appears?
Buzzer sounds?

*

Does not appear.
Does not sound.

Appears.
Sounds.

Request for repair.

End of inspection.

* If nothing appears on the display, the batteries might have beendischarged completely.

— 9 —5-2 Voltage Measurement (Function
DCV
ACV

)

Max. Rated Input
Range
400.0 mV, 4.000 V, 40.00 V, 400.0 V, 600 V
DC 600 V
AC 600 V
4.000 V, 40.00 V, 400.0 V, 600 V
Example of DCV Example of ACV
measurement
measurement

DCV and ACV
Selection

Remarks:
This meter’s AC detection method is the average value method.
It indicates an average value of voltage or current in thepositive half cycle. No error will occur in measurement ofwaveforms when the input waveform is sinusoidal wave with nodistortion. However, if the input waveform is distorted
sinusoidal wave or non-sinusoidal wave, an error will occur.
• The indication may fluctuate when the test leads are released.
It is not a failure.
• The AC 400.0 mV range can be selected with the
button, but the accuracy is not guaranteed.
• In the AC 4.000 V range, when the measuring terminals areshorted, 7 counts maximum may remain indicated.
• The accuracy guarantee frequency range of ACV
measurement is 40 Hz to 400 Hz.
If the frequency is above 1 kHz, measurement is not possible.
• It may malfunction when measuring voltage in the inverter
circuit.
— 10 —

5-3 Resistance Measurement (), Diode Test (), Continuity Check ()

WARNING

Never apply a voltage to the measuring terminals.
5-3-1 Resistance measurement (FunctionMax. Rated Input
40.00 MΩResistor

5-3-2 Diode test (Resistancemeasurement
Diode test
Continuity check
Selection

)

)

Range
400.0 Ω, 4.000 kΩ, 40.00 kΩ,
400.0 kΩ, 4.000 MΩ, 40.00 MΩ
Caution:If measurement is affected bynoises, shield the object tomeasure with COM potential. If
measurement is conducted witha finger touching the test pins, anerror will occur due to influenceof resistance of the human body.
The open voltage between themeasuring terminals is approx.
0.4 VDC.
Forward direction test Reverse direction test

CathodeAnodeRemarks:

The open voltage
between themeasuringterminals isapprox. 1.5 VDC.

Good: OL shown
Good: Forward
voltage drop shown Bad: Other indication
Bad: 0.000 V shown
OL shown— 11 —

5-3-3 Continuity check (Remarks:
Continuity buzzer
sound range:
0 ~ 85 (±45 ))Resistancemeasurement
Diode test
Continuity check
Selection

5-4 Frequency Measurement ()

CAUTION
Never use the meter for measuring frequencies
to ground as the earth leakage breaker may trip.
FunctionMax. Rated Input
100.0 kHz( 600 Vrms)

Measurement
prohibited

Range
5.000 Hz, 50.00 Hz, 500.0 Hz, 5.000 kHz,50.00 kHz, 100.0 kHz (Auto range only)
Remarks:
Because the Hz function uses
input resistance as low as
approx.2 2kk ,, aa large
large amount of
aboutcurrent will flow during
measurement. Never use themeter for measuring circuits ordevices having a small current
capacity.

— 12 —

Remarks:• Input sensitivity: 3 Vrms or over.
• Zero cross (+ potential- potential+ potential) frequencies can bemeasured. Frequencies of + potential only or – potential only such as
logic pulses cannot be measured.
• Frequencies less than 1 Hz cannot be measured.
• When the Hz function is used, the data hold and relative functions
cannot be used.
5-5 Capacitance Measurement ()

WARNING

Never apply a voltage to the measuring terminals.

CAUTION
1. Remove electric charge in the capacitor prior to measurement.
2. Because this meter applies a current to the capacitor to measure, it is
not suitable for measurement of electrolytic capacitors having a large
leak current as a large error will occur.
3. For capacitors having large capacitance, measurement takesa longer time.
Function
CAP ()

Max. Rated Input
100.0 µF

Cancelindicatedvalue prior tomeasurement.

Range
50.00 nF, 500.0 nF, 5.000 µF,
50.00 µF, 100.0 µF (Auto range)
Remarks:• For capacitance measurement,press thebutton tocancel the indicated value(00.00 nF) before connecting acapacitor.
• Only the auto range is available
for the capacitance measuringfunction.
• The indication may not become
stable due to influence ofsurrounding noises or stray
capacitance of the test leads.

— 13 —

5-6 Current Measurement ( A/mA)

WARNING

1. Never apply a voltage to the measuring terminals.
2. Never apply an input exceeding the maximum rated current.
3. Be sure to connect the meter in series via a load.
Correct measuringmethodWrong measuringmethodLoadPower supply

Power supply
Load

CAUTIONBe sure that the built-in fuse has not blown.
Function
DC/AC µA
DC/AC mA

DCA and ACA
Selection

Max. Rated Input
4000 µA
400 mA

Range
400.0 µA, 4000 µA
40.00 mA, 400.0 mA

Remarks:• In current measurement, the internal resistance ofthe current range is placed in series and thecurrent drops by this resistance. Accordingly, its
influence becomes larger in low-resistance circuits.
• The AC accuracy guarantee frequency range isfrom 40 Hz to 400 Hz.
• Current range: Auto range for 400.0 µA ~ 4000 µA
and 40.00 mA ~ 400.0 mA. The range can be
fixed by the RANGE HOLD button.
— 14 —A • mA measurement
Load

Power supply

Function Input Terminal
andBuilt-in Fuse
0.5 A/250 VFuse
Breaking capacity1.5 kA• If the indication will change little when an input signal is applied ora current value which is significantly smaller than the expectedvalue is indicated, possible causes are the input terminals,
incorrect setting of the function switch, or blown fuse. Check theseplaces.

— 15 —

[6] MAINTENANCEWARNING

1. The following instructions are very important for safety.
Read this manual thoroughly to ensure correct maintenance.
2. Calibrate and inspect the meter at least once a year to ensure
safety and maintain its accuracy.
6-1 Maintenance and Inspection
1) Appearance: Is the meter not damaged due to falling or othercause?
2) Test leads:• Are the core wires not exposed from the test leads?
• Is the plug when inserted to the input terminal not loose?
If any of the above problems exists, stop using the meter andrequest for repair.
6-2 Calibration and Inspection
For more information, please contact Sanwa’s authorized agent /distributors. service provider, listed in our website.
See section 7-3.
6-3 Storage

CAUTION

1. The panel and case are not resistant to volatile solvent and mustnot be cleaned with thinner or alcohol.
2. The panel and case are not resistant to heat. Do not place themeter near heat-generating devices.
3. Do not store the meter in a place where it may be subjected tovibration or where it may fall.
4. Do not store the meter in places under direct sunlight, or hot, coldor humid places or places where condensation is anticipated.
5. If the meter will not be used for a long time, remove the batteries.
6-4 Battery and Fuse Replacement

Batteries when the meter is shipped:

A battery for monitoring has been installed prior to shipment fromthe factory. It may be discharged before the expiration of thedescribed battery life.
*The battery for monitoring is a battery used to check thefunctions and performance of the product.
— 16 —

WARNING

1. To avoid electric shock, do not remove the rear case with an
input being applied to the measuring terminals. Also, before
starting replacement, make sure the power of the meter is OFF.
2. Be sure to use the replacement fuse of the same rating. Neveruse a substitute for the fuse nor short the meter.
6-4-1 Battery replacement
Remove the fixing screw of the battery holder with ascrewdriver.
Replace both two batteries in the battery holder with new ones.
(Pay attention to their polarities.)
Set and secure the battery holder with the fixing screw as before.
Battery:
R6 x 2 pieces

6-4-2 Fuse replacement
Remove the screws of the body rear case with a screwdriver.
Take out the fuse and replace it with a new one.
Secure the rear case with the screws as before.

Fuse

Fuse rating: 0.5 A/250 V (ø5 x 20 mm, Breaking capacity1.5 kA）* Spare fuse storage is provided at the bottom of the rear case.
— 17 —

[7] After-Sale Service
7-1 Warranty and Provision
Sanwa offers comprehensive warranty services to its end-users
and to its product resellers. Under Sanwa's general warranty
policy, each instrument is warranted to be free from defects inworkmanship or material under normal use for the period of one(1) year from the date of purchase.
This warranty policy is valid within the country of purchase only,
and applied only to the product purchased from Sanwa authorized
agent or distributor.
Sanwa reserves the right to inspect all warranty claims todetermine the extent to which the warranty policy shall apply. This
warranty shall not apply to disposables batteries, or any productor parts, which have been subject to one of the following causes:
1. A failure due to improper handling or use that deviates from the
instruction manual.
2. A failure due to inadequate repair or modification by people
other than Sanwa service personnel.
3. A failure due to causes not attributable to this product such as
fire, flood and other natural disaster.
4. Non-operation due to a discharged battery.
5. A failure or damage due to transportation, relocation or
dropping after the purchase.
7-2 Repair
Customers are asked to provide the following information whenrequesting services:
1. Customer name, address, and contact information
2. Description of problem
3. Description of product configuration
4. Model Number
5. Product Serial Number
6. Proof of Date-of-Purchase
7. Where you purchased the product— 18 —

Please contact Sanwa authorized agent / distributor / service
provider, listed in our website, in your country with above
information. An instrument sent to Sanwa / agent / distributor
without above information will be returned to the customer.
Note:1) Prior to requesting repair, please check the following:
Capacity of the built-in battery, polarity of installation anddiscontinuity of the test leads.
2) Repair during the warranty period:
The failed meter will be repaired in accordance with theconditions stipulated in 7-1 Warranty and Provision.
3) Repair after the warranty period has expired:
In some cases, repair and transportation cost may become
higher than the price of the product. Please contact Sanwa
authorized agent / service provider in advance.
The minimum retention period of service functional parts is 6
years after the discontinuation of manufacture. Thisretention period is the repair warranty period. Please note,however, if such functional parts become unavailable forreasons of discontinuation of manufacture, etc., the retention
period may become shorter accordingly.
4) Precautions when sending the product to be repaired
To ensure the safety of the product during transportation,
place the product in a box that is larger than the product 5
times or more in volume and fill cushion materials fully andthen clearly mark “Repair Product Enclosed” on the box
surface. The cost of sending and returning the product shallbe borne by the customer.
7-3 SANWA web site
http://www.sanwa-meter.co.jp
E-mail: exp_sales@sanwa-meter.co.jp— 19 —

[8] SPECIFICATIONS
8-1 General Specifications- method
Operation method
AC measuring method Average value method
4000 counts
LCD
Approx. 3 times/sec.
Sampling rate
Auto and Manual (Some with Manual only or Auto only)
Range selection
Over-range indication “OL” shown in numerical part. (600 V DC/AC excluded.)“ - ” indicated only when negative input.
Polarity indication
automatic selection) mark lights or flickers at approx.
Battery low warning Battery (2.4 V or below.
Environmental condition Altitude 2000 m or below, pollution degree II.
5 ˚C to 40 ˚C and humidity range as follows. No condensation allowed.
Operatingtemperature / humidity At 5 ˚C to 31 ˚C, 80 % RH (max). At 31 ˚C to 40 ˚C, linear drop from
80 % RH to 50 % RH.
Storage temperature / -10 ˚C ~ 40 ˚C, 80 %RH max., no condensation
40 ˚C ~ 50 ˚C, 70 %RH max., no condensation
humidity(When the meter will not be used for a long time, remove the batteries before storage.)
SUM-3 (R6P), 2 pieces
Power supply
About 400 hours continuously at DCV. (AutoBattery life
power off canceled)Power off about 30 minutes after no operation.
Auto power off
0.5 A/250 V, Breaking capacity1.5 kA
Fuse
166(L) x 82(W ) x 44(D ) mm (Projections not included)
Dimensions
Approx. 340 g (batteries included)
Mass
Power consumption Typical 4.5 mW (at DCV)
Test lead (TL-21a), Instruction manual
Standard
accessories included
Optional accessories Alligator clip: CL-14, CL-13a, CL-15a,
CL-DG3a, TL-9IC
Clamp probe: CL-22AD, CL-33DC, CL3000
High voltage probe: HV-60
Carrying case: C-77, C-77H— 20 —

8-2 Measuring Range and Accuracy

Temperature: 23±5 ˚C, humidity: 80 % RH max. (no condensation),
voltage 2.4 V or above.
rdg (reading): Read value, dgt (digit): Number of counts of last digit

DCV
Range
400.0 mV
4.000 V
40.00 V
400.0 V
600 V

ACV

Range
4.000 V

Accuracy±(0.5 %rdg+2dgt)±(0.9 %rdg+2dgt)

Accuracy

40.00 V
400.0 V±(1.2 %rdg+7dgt)

600 V

Input ResistanceApprox. 100 MΩ
Approx. 11 MΩ

Remarks

Approx. 10 MΩ

Input Resistance
Remarks
Approx. 11 MΩ ･ Frequency range: 40 Hz ~ 400 Hz(sinusoidal wave)･ If the frequency is above 1 kHz,measurement is not possible.
Approx. 10 MΩ
･ If may malfunction whenmeasuring voltage in the inverter
circuit.

Resistance
Range
400.0 Ω4.000 kΩ40.00 kΩ
400.0 kΩ
4.000 MΩ
40.00 MΩ

Accuracy±(1.2 %rdg+5dgt)±(2.0 %rdg+3dgt)±(3.0 %rdg+3dgt)

Remarks･ Open circuit voltage: Approx. 0.4 VDC･ The measuring current varies depending on
resistance of resistors to measure.

Diode test
Open circuit voltage: Approx. 1.5 VDCContinuity checkContinuity buzzer sound range: 0 Ω ~ 85 Ω (±45 Ω)Open circuit voltage: Approx. 0.4 VDC— 21 —

Frequency
Range

Accuracy

Remarks±(0.3 %rdg+3dgt)･ Auto range only.
･ The data hold and relative functions cannot
be used.
･ Sensitivity: 3 Vrms or over.
･ Frequency less than 1 Hz cannot bemeasured.
･ Input resistance Approx. 2 kΩBecause the input resistance is as low as
approx. 2 kΩ, a large amount of current willflow during measurement. Never use themeter for measuring circuits or devices
having a small current capacity.
Never use the meter for measuring
frequencies to ground as the earth leakage
breaker may trip.

5.000 Hz50.00 Hz500.0 Hz5.000 kHz50.00 kHz
100.0 kHzCapacitanceRange
50.00 nF
500.0 nF
5.000 µF
50.00 µF
100.0 µF

DCA

Range
400.0 µA
4000 µA
40.00 mA
400.0 mA

ACA

Range

Accuracy

Remarks±(5.0 %rdg+10dgt)･ Accuracy after canceling the indicatedvalue by the relative function.
･ Auto range only

Accuracy±(1.4 %rdg+3dgt)

Accuracy

400.0 µA
4000 µA
40.00 mA
400.0 mA

Input Resistance

Remarks

Approx. 100 Ω ･ The input resistanceexcludes the fuse
Approx. 1 Ωresistance.
Input ResistanceApprox. 100 Ω±(1.8 %rdg+5dgt)
Approx. 1 Ω— 22 —

Remarks･ Accuracy guarantee
frequency range:
40 Hz ~ 400 Hz(sinusoidal wave)･ The input resistanceexcludes the fuseresistance.

* Accurate measurement may not be possible in places near atransformer, large-current line, etc. where a strong magnetic field
is present or near radio equipment, etc. that generates a strong
electric field.
Accuracy calculation
Example: DCV function
True value: 100 mV
Range accuracy: 400 mV range …±(0.5 %rdg+2dgt)
Error: ±(100.0 mV x 0.5 % + 2dgt) = ±0.7 mV
Indicated value: 100.0 mV ± 0.7 mV (in a range of 99.3 mV and
100.7 mV)The product specifications described in this manual and its
appearance are subject to change without notice for improvement orother reasons.

— 23 —

本社=東京都千代田区外神田2−4−4･電波ビル
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