770A
DIGITAL MULTIMETER
OPERATOR’S MANUAL
1.
Overview
The multimeter is characterized at slim size, portable, stable performance and
anti-dropping capacity. Using 3 1/2 digits LCD monitor with character 28mm high,
they offer clear readings.
With overall circuitry design centering on large-scale IC
A/D converters in conjunction and over-load protection circuit, the meters give
excellent performance and exquisite making as a handy utility instrument.
The meters can be used to measure DC & AC voltage, DC & AC current, resistance,
capacitor, transistor hFE, Non Contact AC Voltage (NCV) detection, positive diode
voltage fall and audible continuity.
2. Panel Layout
1
NCV detection area: Non Contact AC Voltage (NCV) detection area.
2
CDS sensor: The CDS sensor can reaction to the ambient brightness range,
then automatically control the LCD backlight to lighten or go out.
3
NCV red light: Non Contact AC Voltage (NCV) detection red light.
4
NCV green light: Non Contact AC Voltage (NCV) detection green light.
5
LCD display: 3 1/2 digits LCD display.
6
POWER key: Press the “POWER” key to power on or off the meter.
7
HOLD key: Press the “HOLD” key to lock display value, and the “
” sign will
appear on the display, press it again to exit.
8
NCV Key: Press and hold the “NCV” key, the meter enters Non Contact AC
Voltage (NCV) detection, the NCV green LED light will light up, free it to exit.
9
Rotary Switch: Use this switch to select functions and ranges.
10
mA
: mA and capacitor Input Jack
11
20A: 20A Input Jack
12
VΩ
: V
Input Jack
13
COM: COM Input Jack
14
Transistor hFE test Input Jack
15
Crust of meter
16
Protective casing
3. Safety Information
3-1 The meter is designed according to IEC-1010 concerning electronic measuring
instruments with an over-voltage category 1000V (CAT
Ⅲ
) and pollution 2.
3-2 Follow all safety and operating instructions to ensure that the meter is used
safely and is kept in good operating condition.
3-3 safety symbols:
Important safety information, refer to the operating manual.
Dangerous voltage may be presence.
Double insulation (protection Class II)
4. Special Cautions for Operation
4-1 The meters can be safe only according to standard procedures when used in
conjunctions with the supplied test leads. To replace damaged test leads with only
the same model or same electric specifications.
4-2 To avid risk of electric shock, do not use the meters before the cover is in place.
4-3 The range switch should be right position for the testing.
4-4 To avoid electric shock and damaging the instruments, the input signals are
forbidden to exceed the specified limits.
4-5 When measuring TV set or switched power, attention should be paid to the
possible pulses that may bring destruction to the circuit.
4-6 Range switch position is forbidden to be changed at random during
measurement.
4-7 Take caution against shock in the course of measuring voltage higher than DC
60V & AC 30V.
4-8 Protection fuse should be replaced only with same type and same specification.
4-9 After operation is finished, power OFF the meter to save battery power.
4-10 If the meter is without usage for long time, take out battery to avoid damage by
battery leakage.
5. GENERAL SPECIFICATIONS
5-1 Max Voltage between input terminal and Earth Ground: CAT
Ⅲ
1000V
5-2 Over-range Indication: display “1” or “-1” for the significant digit.
5-3 Automatic display of negative polarity “-” .
5-4 Low Battery Indication: “ ” displayed.
5-5 Display: 3 1/2 digit LCD with a max. reading of 1999.
5-6 Manual range control
5-7 Auto Power Off: The meter will switch to standby mode when power on after
approx. 20 minutes. Press the “POWER” key two times to power on the meter
again.
5-8 Auto LCD backlight
5-9 Fuse protection: 200mA/500V & 20A/500V Fast Fuse
5-10 Power supply: 9V battery (6F22 or NEDA 1604)
5-11 Operating Temp. : 0
℃
to 40
℃
(relative humidity <85%)
5-12 Storage Temp. : -10
℃
to 50
℃
((relative humidity <85%)
5-13 Guaranteed precision Temp. : 23
±
5
℃
(relative humidity <70%)
5-14 Dimension: 195x88x40mm
5-15 Weight: approx. 350g (including battery)
6. Testing Specifications
Accuracy is specified for a period of year after calibration and at 18
℃
to 28
℃
(64
℉
to 82
℉
) with relative humidity to 70%.
6-1 DC Voltage
Range
Resolution
Accuracy
200mV
0.1mV
±(0.5% of rdg + 2 digits)
2V
1mV
20V
10mV
200V
100mV
1000V
1V
±(0.8% of rdg + 2 digits)
-- Impedance: 10MΩ
-- Overload protection: 1000V DC or 750V AC rms
6-2 AC Voltage
Range
Resolution
Accuracy
2V
1mV
±(1.0% of rdg + 2 digits)
20V
10mV
200V
100mV
750V
1V
±(1.2% of rdg + 3 digits)
-- Impedance: 10MΩ (2V range is 1MΩ)
-- Overload protection: 1000V DC or 750 AC rms
-- Frequency Range: 40 to 400Hz
-- Response: average, calibrated in rms of sine wave
6-3 DC Current
Range
Resolution
Accuracy
2mA
1μA
±(1.2% of rdg + 2 digits)
20mA
10μA
200mA
100μA
20A
10mA
±(2.0% of rdg + 3 digits)
-- Overload protection: 200mA/500V & 20A/500V Fast Fuse
Note: 20A up to 10 seconds
6-4 AC Current
Range
Resolution
Accuracy
2mA
1μA
±(1.5% of rdg + 3 digits)
200mA
100μA
20A
10mA
±(2.5% of rdg + 5 digits)
-- Overload protection: 200mA/500V & 20A/500V Fast Fuse
Note: 20A up to 10 seconds
-- Frequency Range: 40 to 400Hz
-- Response: average, calibrated in rms of sine wave
6-5 Resistance
Range
Resolution
Accuracy
200Ω
0.1Ω
±(1.0% of rdg + 3 digits)
2kΩ
1Ω
±(1.0% of rdg + 2 digits)
20kΩ
10Ω
200kΩ
100Ω
20MΩ
10kΩ
±(1.5% of rdg + 3 digits)
200MΩ
100kΩ
±(5.0% of rdg + 10 digits)
-- Overload protection: 500V DC or AC rms
6-6 Capacitance
Range
Accuracy
Resolution
2nF
±(2.5% of rdg + 5 digits)
1pF
20nF
10pF
200nF
100pF
2µF
1nF
20µF
10nF
200µF
±(5.0% of rdg + 10 digits)
100nF
-- Overload protection: 200mA/500V Fast Fuse
6-7 Diode and Audible continuity test
Range
Description
Test Condition
Display read approximately
forward voltage of diode
Forward DC current
approx. 1mA
Reversed DC voltage
approx. 3V
Built-in buzzer sounds if
resistance is less than 50Ω
Open circuit voltage
approx. 3V
Overload protection: 500V DC or AC rms
6-8 Transistor hFE test
Test range: 0-1000
Ib=10µA, Vce=3.0V Approx.
6-9 Non Contact AC Voltage (NCV) detection
Test voltage range: 90V
～
1000V AC rms
The NCV red LED light and green LED light will light up alternately together with
sound.
