twintex TM187 Operation Manual

DIGITAL MULTIMETER

OPERATION MANUAL
1. GENERAL
This digital multimeter is a steady performance, battery-driven 4 1/2
digital multimeter. It uses the LCD with 28mm high figure to make the reading
clear and make operation more convenient.
The digital multimeter has the function of measuring DCV, ACV, DCA, ACA,
resistance, capacitance, transistor and diode, and continuity performance test,
etc. The meter can provide functions including unit symbol display, data
holding, It adopts double integral A/D converter as its core. It is an ideal
tool for labs, factories and radio-technology.
2. SAFETY
The instrument is designed according to IEC1010 standard (safety standard
issued by International Electro technical Committee). Please read the safety
note before operation.
2-1. Do not input a limited voltage higher than DC 1000V or AC 750V when
measuring ranges.
2-2. The voltage below 36V is safety. To avoid electric shock, check whether
the test leads are connected correctly, whether the insulation is good when
measuring over 36DCV or 25ACV.
2-3. The test leads should be removed from the testing point when changing
function and range.
2-4. Choose correct function and range to avoid wrong operation.
2-5. Do not input current higher than 20A when measuring current.
2-6. Specification of safety signal
" existing dangerous volt " " GND " "dual insulation
"
" " operator must refer to the manual " "low battery indication
3. SPECIFICATION
3-1．GENERAL
3-1-1. Displaying: LCD display
3-1-2. Max. displaying：19999（4 1/2）auto-polarity display
3-1-3. Measuring method：dual-slope A/D transfer
3-1-4. Sampling rate：approx. 3 times/sec
3-1-5. Over-range display: "1" or "-1"displayed in the highest digit.
3-1-6. Low battery display：" " displays
3-1-7. Operation ：(0～40)℃，relative humidity <80% R.H
3-1-8. power: 9V battery (NEDA1604/6F22 or equivalent)
3-1-9. Dimension: 185mm×93mm×35 mm
3-1-10. Weight: approx. 290g (including battery)
3-1-11. Accessories: user manual, test leads, holster, gift box, and 1*9V
battery.
3-2．TECHNICAL SPECIFICATION
3-2-1. Accuracy: ±（a% × reading＋digits）at 23 ± 5℃，<75% R.H，one year
guarantee from production time.
3-2-2.DCV
Range Accuracy
200mV
2V
±(0.1%+5)
20V
200V
1000V ±(0.2%+5)
Input impedance：10MΩ at all ranges
Over-range protection：250 DCV or AC peak value at 200mV range,
3-2-2.AC
Range
2V
20V
200V
750V
Input impedance：10MΩ at all ranges
Over-range protection：1000 DCV or DC peak value at other range
Frequency response：below 200V：40~400Hz，750Vrange:40~200Hz
Displaying：sine wave RMS（mean value response ）
3-2-3.DCA
Range
200uA
2mA
20mA
200mA
20A
Max. measuring volt drop: 200mV
Max. input current: 20A（less than10 seconds）
Overload protection: 0.2A / 250V fast blow fuse; 20A range without fuse.
3-2-4.ACA
Range
200mA
20A
Max. measuring volt drop：200mV
Max. input current：20A（less than 10 seconds）
Overload protection： 0.2A / 250V with fuse，20A range without fuse.
Frequency response：40~200Hz
Displaying：sine wave RMS（mean value response）
3-2-5. RESISTANCE（Ω）
Range
200Ω
2kΩ
20kΩ
200kΩ
2MΩ
20MΩ
Open circuit voltage：less than 3V;
Overload protection：250DCV or ACV peak value;
Note:
In 200Ω range ， should make the test leads short, and measure the
resistance of the wire, then, subtracts from the actual measuring value.
3-2-6. Conductance（resistance range:10,000MΩ-10MΩ）
Resolution
Range
10uV
(0.1-100)nS
100uV
Open circuit voltage：less than 3V;
1mV
10mV
100mV
1000 DCV or DC peak value at other range
Accuracy Resolution
100uV
±(0.8%+25)
1mV
10mV
±(1.0%+25) 100mV
Accuracy Resolution
0.01uA
±(0.5%+4) 0.1uA
1uA
±(0.8%+6) 10uA
±(2.0%+15) 1mA
Accuracy Resolution
±(1.5%+25) 10uA
±(2.5%+35) 1mA
Accuracy Resolution
±(0.2%+10) 0.01Ω
0.1Ω
1Ω
±(0.2%+5)
10Ω
100Ω
±(0.8%+15) 1kΩ
Accuracy Resolution
±(1.0+5) nS
3-2-7.CAPACITANCE
Range Accuracy
20nF
±(3.5%+10)
2uF
200uF ±(3.8%+20)
Testing frequency: 400Hz;
Overload protection：36 DCV or ACV peak value.
3-2-8.FREQUENCY
Range Accuracy
2kHz
±(3.0%+15)
200kHz
Input sensitivity：1V RMS;
Overload protection：250V DC or AC peak value (less than 10sec.).
3-2-9.DIODE AND CONTINUITY TEST
RANGE DISPLAYING VALUE
Forward DC current is
Diode forward volt drop approx. 1mA ， backward
voltage is approx. 3V
Buzzer rings, the impedance
Open voltage is approx.
between the two testing points
3V
is less than(30±10)Ω
Overload protection：250DCV or ACV peak value;
Warning: do not input any voltage value at this range for safety!
3-2-10. hFE
Range Scope Testing condition
Base DC current is approx.
hFE NPN or PNP 0~1000
10uA，V
4.OPERATION
4-1．Front panel
①. LCD: display the measured value;
②Function key;
②-1. Power switch: turn on or off the power
②-2. HOLD key: press the key down, the measured value
will be hold and "HOLD" signal appears; press it
down again," HOLD "signal disappears and out of
the HOLD mode.
②. Backlight;
③．hFE testing terminal：for measuring transistor
hFE;
④．Knob switch: for changing function and range;
⑤．Terminal for capacitance;
⑥．Terminal for Voltage, resistance, frequency and GND testing;
⑦．Battery case;
4-2．DCV measurement
4-2-1. Apply the black test leads to "COM" terminal and the red one to V/Ω/Hz
terminal.
4-2-2. Switch the knob to a proper DCV range, then, connect the test leads cross
the measured circuit, the voltage and polarity of the point which connected
with the red test lead will be displayed.
NOTE:
1. If the voltage under measured is unclear beforehand, should set the range
knob to the highest range, then, switch to a proper range according to the
displaying value.．
2. The remained digits do not affect on measuring accuracy when we haven't
Resolutio
1pF
100pF
10nF
Resolutio
0.1Hz
10Hz
TEST CONDITION
is approx. 3V
ce