770D
DIGITAL MULTIMETER
OPERATOR’S MANUAL
1. Overview
The multimeter is characterized at slim size, portable, stable performance and anti-dropping
capacity. Using 40000 counts digit & analogue bar graph LCD monitor with character 16.5mm
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,
frequency, duty cycle, temperature, 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: 40000 counts digit & analogue bar graph, full function symbol display.
6
SELECT key: This key work on the "
" range, press the key to choose resistance,
diode or continuity test, on the voltage or current range, change to DC or AC, on the
range, change to
℃
or
℉
test; If press and hold SELECT key to power on, “Auto
Power Off ” function will be disabled.
7
RANGE Key: Press the “RANGE” key, the meter enters manual range mode, press it more
than 2 seconds again, return to auto mode.
8
REL
▲
Key: Press the “REL
▲
” key, the meter enters relative measuring mode, “REL” is
displayed on the LCD and the present reading becomes the reference value and displayed
on the display. Relative measurement REL
△
=measurement value-Reference value. Press
it again to exit.
9
Hz/Duty Key: On “ACV/ACA” or “Hz” range, press the “Hz/Duty” key, you can choose the
Frequency or Duty Cycle measurement.
10
HOLD key: Press the “HOLD” key to lock display value, and the “DH” sign will appear on
the display, press it again to exit.
11
MAX/MIN key: Press the “MAX/MIN” key to lock MAX or MIN value, and the “MAX” or
“MIN” sign will appear on the display, press it over 2 seconds to exit.
12
Rotary Switch: Use this switch to select functions and ranges.
13
μAmAT+: μAmAand Temperature “+” Input Jack
14
20A: 20AInput Jack
15
VΩHz
: V/Hz/
Input Jack
16
COMT-: COM and Temperature “-” Input Jack
17
Transistor hFE test Input Jack
18
Crust of meter
19
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, set function switch at OFF 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 “OL” for the significant digit.
5-3 Automatic display of negative polarity “-” .
5-4 Low Battery Indication: “
” displayed.
5-5 Max LCD display: 40000 counts digit & analogue bar graph.
5-6 Auto range & Manual range control
5-7Auto Power Off: When measurement exceeds 15 minutes without switching mode and
pressing key, the meter will switch to standby mode. Press any key to exit standby mode.
When restart the system, press and hold SELECT key to disable auto power off.
5-8 Auto LCD backlight
5-9 Fuse protection: 500mA/500V Fast Fuse, 20A/500V Fast Fuse
5-10 Power supply: 9V 6F22 battery
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
40mV
1μV
±(0.1% of rdg + 5 digits)
400mV
10μV
±(0.1% of rdg + 2 digits)
4V
100μV
40V
1mV
400V
10mV
1000V
100mV
±(0.1% of rdg + 5 digits)
-- Impedance: 10MΩ, More than 100MΩ on 40mV/400mV range
-- Overload protection: 1000V DC or 750V AC rms
6-2 AC Voltage (True RMS)
Range
Resolution
Accuracy
40mV
1μV
±(1.0% of rdg + 10 digits)
400mV
10μV
±(0.8% of rdg + 10 digits)
4V
100μV
40V
1mV
400V
10mV
750V
100mV
±(1.2% of rdg + 10 digits)
-- Impedance: 10MΩ, More than 100MΩ on 40mV/400mV range
-- Overload protection: 1000V DC or 750V AC rms
-- Frequency Range: 40 to 1kHz
6-3 DC Current
Range
Resolution
Accuracy
400μA
0.01μA
±(1.0% of rdg + 10 digits)
4000μA
0.1μA
40mA
1μA
400mA
10μA
4A
100μA
±(1.2% of rdg + 10 digits)
20A
1mA
-- Overload protection: 500mA/500V Fast Fuse, 20A/500V Fast Fuse, 20A up to 10 seconds
6-4 AC Current (True RMS)
Range
Resolution
Accuracy
400μA
0.01μA
±(1.2% of rdg + 10 digits)
4000μA
0.1μA
40mA
1μA
400mA
10μA
4A
100μA
±(1.5% of rdg + 10 digits)
20A
1mA
-- Overload protection: 500mA/500V Fast Fuse, 20A/500V Fast Fuse, 20A up to 10 seconds
-- Frequency Range: 40 to 400Hz
6-5 Resistance
Range
Resolution
Accuracy
400Ω
0.01Ω
±(1.0% of rdg + 10 digits)
4kΩ
0.1Ω
±(0.5% of rdg + 10 digits)
40kΩ
1Ω
400kΩ
10Ω
4MΩ
100Ω
40MΩ
1kΩ
±(1.0% of rdg + 10 digits)
-- Overload protection: 500V DC or AC rms
6-6 Capacitance
Range
Accuracy
Resolution
9.999nF
±(5.0% of rdg + 10 digits)
1pF
99.99nF
±(3.0% of rdg + 10 digits)
10pF
999.9nF
±(2.5% of rdg + 5 digits)
100pF
9.999µF
1nF
99.99µF
±(5.0% of rdg + 10 digits)
10nF
999.9µF
±(10.0% of rdg + 20 digits)
100nF
9.999mF
1µF
99.99mF
10µF
-- Overload protection: 500V DC or AC rms
6-7 Frequency
Range
Accuracy
Resolution
9.999Hz
± (0.1% of rdg + 5 digits)
0.001Hz
99.99Hz
0.01Hz
999.9Hz
0.1Hz
9.999kHz
1Hz
99.99kHz
10Hz
999.9kHz
100Hz
9.999MHz
1kHz
