Extech Instruments 380941 User manual

User Guide
AC/DC Mini Clamp Meter
Model 380941

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Introduction
Congratulations on your purchase of Extech’s DC/AC Clamp Meter. This professional meter, with
proper care, will provide years of safe reliable service.
Front Panel Description
1. Current sense jaw
2. Measurement Trigger
3. Function switch
4. Data Hold key
5. Max Min key
6. One-touch DCA zero key
7. LCD Display
8. 40 segment bargraph display
9. Positive input terminal for V, HZ and 
10. COM termin
International Symbols
!Caution ! Refer to the explanation in this Manual
Caution ! Risk of electric shock
Earth (Ground)
Safety
This meter has been designed to be safe in use, but the operator must use caution in its operation.
The rules listed below should be carefully followed for safe operation.
1. NEVER apply voltage or current to the meter that exceeds the specified maximum:
2. USE EXTREME CAUTION when working with high voltages.
3. DO NOT measure voltage if the voltage on the "COM" input jack exceeds 500V above earth
ground.
4. NEVER connect the meter leads across a voltage source while the function switch is in the
current, resistance or diode mode; doing so can damage the meter.
5. ALWAYS discharge filter capacitors in power supplies and disconnect the power when making
resistance or diode tests.
6. ALWAYS turn off the power and disconnect the test leads before opening the back to replace
the fuse or batteries.
7. NEVER operate the meter unless the back cover and the battery/fuse door are in place and
fastened securely.

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Operation
AC Current Measurements
WARNING: To avoid electric shock, disconnect the test leads from the meter before making current
measurements.
1) Set the Function switch to the 40 or 200A AC range.
2) Press the jaw trigger and clamp around, fully enclosing a single conductor. Do not allow a gap
between the two halves of the jaw.
3) Read the ACA value on the LCD.
DC Current Measurements
WARNING: To avoid electric shock, disconnect the test leads from the meter before making current
measurements.
1) Set the Function switch to the 40 or 200A DC range.
2) Press the DCA zero key to null the meter display.
3) Press the Trigger to open the current sense Jaw.
4) Fully enclose the conductor to be measured. Do not allow a gap between the two halves of
the jaw.
5) Read the DCA value on the LCD.
AC Voltage Measurements
WARNING: To avoid electric shock or damage to the meter, do not make any voltage
measurements that exceed the maximum specified.
1) Set the Function switch to the VAC position.
2) Insert the test leads to the meter as follows: Red lead to “V,Hz,” terminal; Black lead to the
COM input.
3) With the pointed end of the test leads measure voltage. Remember that voltage
measurements are made in parallel with the device or circuit under test.
4) Read the ACV value on the LCD.
DC Voltage Measurements
WARNING: To avoid electric shock or damage to the meter, do not make any voltage
measurements that exceed the maximum specified.
1) Set the Function switch to the VDC position.
2) Insert the test leads to the meter as follows: Red lead to “V,Hz,” terminal; Black lead to the
COM input.
3) With the pointed end of the test leads measure voltage. Remember that voltage
measurements are made in parallel with the device or circuit under test.
4) Read the DCV value on the LCD.

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Resistance and Continuity Measurements
WARNING: To avoid electric shock or damage to the meter, remove power to the circuit under test and discharge
all capacitors.
1) Set the Function switch to the position.
2) Insert the test leads to the meter as follows: Red lead to “V,Hz,” terminal; Black lead to the
COM input.
3) With the pointed end of the test leads measure resistance. Remember that resistance
measurements are made in parallel with the device or circuit under test.
4) Read the resistance value on the LCD.
5) If the resistance is less than 40, the continuity beeper will sound.
Frequency Measurements
1) Ensure that at least 0.1A AC is detectable with an ACA measurement before measuring
Frequency.
2) Set the Function switch to the Hz position.
3) Insert the test leads to the meter as follows: Red lead to “V,Hz,” terminal; Black lead to the
COM input.
4) With the pointed end of the test leads measure frequency
5) Read the Frequency measurement on the LCD in Hz.
Additional Features
Relative Measurements
1) Press the Zero key and the present measurement will Zero.
2) All subsequent measurements are displayed with respect to the zeroed reading. For example,
if a 20A reading is zeroed and a 30A reading is subsequently measured, the LCD will display
10A.
3) To return to normal operation, press the zero key one more time.
4) Note that Relative mode is not available if the MIN/MAX mode is enabled.
5) Relative mode is not available in continuity or Hz mode.
6) Note that the Zero button is disabled if ohm and continuity or Hz functions are selected.
7) LCD displays relative numerical value without bargraph.
Data Hold
To freeze a reading on the LCD, press the Data Hold key. The HOLD icon will appear and the
measurement will be held on the meter’s LCD. To release the Data Hold function and return the
meter to normal operation, press the Data Hold key again. Data Hold is disabled if ohm and
continuity function are selected.
MIN/MAX Reading Mode
Pressing the MIN/MAX key allows the meter to display ONLY the highest and the lowest readings
encountered. Press the MIN/MAX key once to view the minimum reading, press it again to view
the maximum reading. The LCD will toggle between the MIN and MAX values. Press and hold
MIN/MAX button for more than 2 seconds to return to normal operating mode. Zero function will
be disabled when MIN/MAX is enabled. MIN/MAX is not available in continuity or Hz mode.

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Specifications
General Specifications
Display 3-3/4 (4032 count) Digit LCD with 40 segment bargraph
Functions ACA, DCA, ACV, DCV, Resistance, Frequency, Continuity
Polarity “-“ indicates negative polarity
Current sensor Hall effect sensor type
Overload indication OL
DCA zero adjust One touch zero key
Display rate 3 readings/second (30 readings/second for bargraph)
Battery Two 1.5V AA batteries
Operating temperature -10oC to 50oC (4oF to 122oF)
Operating humidity < 85% RH
Power consumption Approximately 17mA DC
Sampling time 3 times/sec (display); 30 times/sec (bargraph)
Weight 225g (8 oz.) including battery
Dimensions 183 x 63.6 x 35.6mm (7.2 x 2.5 x 1.4”) (HWD)
Jaw opening 23mm (0.9”)
Standards IEC 1010 Category III 300V, Category II 600V
Range Specifications
Function Range Resolution. Accuracy Overload
protect
DC Current 40A 10mA ±(1.0% +2dgts) 400A DC
0 to 150A 100mA ±(1.0% +2dgts) 400A DC
150 to 200A 100mA ±(2.2% +2dgts) 400A DC
AC Current 50/60Hz 40 to 400Hz
40A 10mA ±(1.0% +3dgts) ±(1.5% +4dgts) 400A AC
0 to 150A 100mA ±(1.0% +3dgts) ±(1.5% +4dgts) 400A AC
150 to 200A 100mA ±(2.2% +3dgts) ±(2.5% ±4dgts) 400A AC
DC Voltage 400V 0.1V ±(1.0% +2dgts) 1000VDC
AC Voltage 50/60Hz 40 to 400Hz
400V 0.1V ±(1.5% +2dgts) ±(2.0% +4dgts) 800V AC
Resistance 40 to 4000.1±(1.0% +2dgts) Beeper <approx
38
600V AC
Frequency 1 to 100k 0.001-100 ±0.5% ±2dgts Sensitivity;
5VAC
600V AC

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Maintenance
Battery Replacement
1) When the low battery symbol appears on the LCD the batteries must be replaced.
2) Turn the meter off and remove the rear battery compartment screw.
3) Remove the battery compartment cover and replace the two 1.5V AA cells.
4) Replace the compartment cover and secure the screw.
You, as the end user, are legally bound (Battery ordinance) to return all used
batteries and accumulators; disposal in the household garbage is prohibited!
You can hand over your used batteries / accumulators at collection points in your
community or wherever batteries / accumulators are sold!
Disposal: Follow the valid legal stipulations in respect of the disposal of the device at the end of its
lifecycle
Cleaning
Caution: Use only a dry cloth to clean the plastic case.
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