Tenma 72-7740 Operating Manual
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Tenma 72-7740 Operating Manual

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Title
A.
Selecting a Measurement Range
I.
A.
DC Voltage
Model 72-7740/72-7745: OPERATING MANUAL
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Summary of Contents for Tenma 72-7740

  • Page 1: Table Of Contents

    DC or AC Current Measurement Operation of Hold Mode The Use of Relative Value Mode The POWER Button The BLUE Button Turning on the Display Backlight Sleep Mode (Model 72-7740 only) General Specifications Accuracy Specifications DC Voltage AC Voltage Resistance...
  • Page 2 Model 72-7740/72-7745: OPERATING MANUAL Page Diode Test Capacitance Frequency & Duty Cycle Temperature DC Current AC Current Maintenance General Service Testing the Fuses Replacing the Battery Replacing the Fuses RS232C Serial Port (Model 72-7745) RS232C Port Cable Setting of RS232C Serial Ports...

  • Page 3: Overview

    To avoid electric shock or personal injury, read the “Safety Information” and “Rules for Safe Operation” carefully before using the Meter. Digital Multimeter Model 72-7740 (hereafter referred to as “the Meter”) have autorange and manual range options with maximum reading 3999. The enclosure structure design adopted advanced “co-injection”...

  • Page 4: Unpacking Inspection

    Model 72-7740/72-7745: OPERATING MANUAL Unpacking Inspection Open the package case and take out the Meter. Check the following items carefully to see any missing or damaged part: Item Description Operating Manual 1 piece Test Lead 1 pair Test Clip 1 pair...

  • Page 5: Rules For Safe Operation

    Model 72-7740/72-7745: OPERATING MANUAL Rules For Safe Operation Warning To avoid possible electric shock or personal injury, and to avoid possible damage to the Meter or to the equipment under test, adhere to the following rules: l Before using the Meter inspect the case. Do not use the Meter if it is damaged or the case (or part of the case) is removed.

  • Page 6: International Electrical Symbols

    Model 72-7740/72-7745: OPERATING MANUAL cable and test clip from the Meter and turn the Meter power off before opening the case. l When servicing the Meter, use only the same model number or identical electrical specifications replacement parts. l The internal circuit of the Meter shall not be altered at will to avoid damage of the Meter and any accident.

  • Page 7: The Meter Structure

    Model 72-7740/72-7745: OPERATING MANUAL The Meter Structure (see figure 1) (figure 1) 1 LCD Display 2 Functional Buttons 3 Rotary Switch 4 HzV Input Terminal: Input for voltage, frequency/duty cycle, resistance, diode, continuity and capacitance measurements. 5 COM Input Terminal: Return terminal for all measurements.

  • Page 8: Rotary Switch

    Model 72-7740/72-7745: OPERATING MANUAL Rotary Switch The table below provides information about rotary switch positions. Rotary Switch Function Position DC voltage measurement range from 400.0mV to 1000V or AC voltage measurement range from 4.000V to 750.0V. Continuity test. Diode test.

  • Page 9: Functional Buttons

    Model 72-7740/72-7745: OPERATING MANUAL Functional Buttons (1) The table below provides information about functional button operation. Button Measuring Operation Performed Function POWER Any rotary Turn the power on and off. switch position Switches between AC and DC voltage; the Meter beeps. DC is default.
  • Page 10 Model 72-7740/72-7745: OPERATING MANUAL Functional Buttons (2) l Press RANGE to enter the Any rotary switch manual ranging mode; the Meter position beeps. exceptHz Manually selecting a range causes the Meter to exit the Hold and REL modes. RANGE l Press RANGE to step through the ranges available for the selected function;...

  • Page 11: Display Symbols

    12 ~ 16 (figure 2) Number Symbol Meaning Indicator for AC voltage or current. Model 72-7740: The displayed value is the mean value. Model 72-7745:The displayed value is the true rms value. TRMS Model 72-7745: Indicator for true rms value.

  • Page 12: Measurement Ranges

    Model 72-7740/72-7745: OPERATING MANUAL Display Symbols (1) (see figure 2) , k , Ohm. The unit of resistance. kilohm. 1 x 10 or 1000 ohms. Megaohm. 1 x 10 or 1,000,000 ohms. Farad. The unit of capacitance. Microfarad. 1 x 10 or 0.000001 farads.
  • Page 13 Model 72-7740/72-7745: OPERATING MANUAL Measurement Ranges (2) l In the autorange mode, the Meter selects the best range for input signals. This allows you to switch test points without having to reset the range. l In the manual range mode, you may select the range.

  • Page 14: Measurement Operation A. Dc Voltage Measurement

    Model 72-7740/72-7745: OPERATING MANUAL Measurement Operation (1) A.DC Voltage Measurement (see figure 3) (figure 3) Warning To avoid harm to you or damage to the Meter from electric shock, please do not attempt to measure voltages higher than 1000VDC / 750VAC rms although readings may be obtained.

  • Page 15: Ac Voltage Measurement

    Model 72-7740/72-7745: OPERATING MANUAL Measurement Operation (2) B. AC Voltage Measurement (see figure 4) (figure 4) Warning To avoid harm to you or damage to the Meter from electric shock, please do not attempt to measure voltages higher than 1000VDC / 750VAC rms although readings may be obtained.

  • Page 16: Measuring Resistance

    Model 72-7740/72-7745: OPERATING MANUAL Measurement Operation (3) C.Measuring Resistance (see figure 5) (figure 5) Warning To avoid damage to the Meter or to the devices under test, disconnect circuit power and discharge all the high-voltage capacitors before measuring resistance. The resistance ranges are: 400.0 , 4.000k , 40.00k 400.0k , 4.000M and 40.00M .

  • Page 17: Testing For Continuity

    Model 72-7740/72-7745: OPERATING MANUAL Measurement Operation (4) l If reading with shorted test leads is not 0.5 , check for loose test leads, incorrect function selection, or enabled Data Hold function. l For high-resistance measurement ( ), it is normal to take several seconds to obtain a stable reading.

  • Page 18: Testing Diodes

    Model 72-7740/72-7745: OPERATING MANUAL Measurement Operation (5) l When continuity testing has been completed, disconnect the connection between the test leads and the circuit under test, and remove the test leads from the input terminals of the Meter. E. Testing Diodes...

  • Page 19: Capacitance Measurement

    Model 72-7740/72-7745: OPERATING MANUAL Measurement Operation (6) voltage drop reading of 0.5V to 0.8V; however, the reverse voltage drop reading can vary depending on the resistance of other pathways between the probe tips. Connect the test leads to the proper terminals as said above to avoid error display.

  • Page 20: Frequency Measurement

    Model 72-7740/72-7745: OPERATING MANUAL Measurement Operation (7) anode & black clip to cathode instead of using test leads as mentioned above. l To minimize the effect of capacitance stored in the test leads, the test lead should be as short as possible. To measure a small value of capacitance, use REL mode to remove the leads capacitance.

  • Page 21: Measuring Duty Cycle

    Model 72-7740/72-7745: OPERATING MANUAL Measurement Operation (8) l To obtain a stable reading when measuring input scope 30V rms frequency signal: Set the rotary switch to V Then press Hz% to select Hz measurement mode to obtain frequency value. When input scope 30V rms, please follow the above step 2.

  • Page 22: Temperature Measurement

    Model 72-7740/72-7745: OPERATING MANUAL Measurement Operation (9) I. Temperature Measurement(see figure 10) (figure 10) The temperature measurement range is measure temperature, connect the Meter as follows: 1. Insert the red temperature probe into the and the black temperature probe into the COM terminal.
  • Page 23 4. The Meter defaults to DC current measurement mode. To toggle between DC and AC current measurement function, press BLUE button. Model 72-7740: AC current is displayed as effective value of sine wave (mean value response). Model 72-7745 : AC current is displayed as true rms value.

  • Page 24: Operation Of Hold Mode

    Model 72-7740/72-7745: OPERATING MANUAL Operation of Hold Mode Warning To avoid possibility of electric shock, do not use Hold mode to determine if circuits are without power. The Hold mode will not capture unstable or noisy readings. The Hold mode is applicable to all measurement functions.

  • Page 25: The Power Button

    Model 72-7740/72-7745: OPERATING MANUAL The POWER button This is a self-lock switch used to turn on or off the power of the Meter. The BLUE button It is used for selecting the required measurement function when more than one function exists at one position of the rotary switch.

  • Page 26: General Specifications

    Model 72-7740/72-7745: OPERATING MANUAL General Specifications l Maximum Voltage between any Terminals and Grounding: 1000V. Fused Protection for Input Terminal: Glass fuse, 0.5A, 250V, fast type, 5x20mm. Fused Protection for 10AInput Terminal: Glass fuse, 10A, 250V, fast type, 5x20mm. l Maximum Display: Digital: 3999 l Measurement Speed: Updates 3 times/second.

  • Page 27: Accuracy Specifications

    750V AC rms 100mV 400V continuous. 750V (1.2%+5) Remarks: l Input impedance 10M l Model 72-7740: displays effective value of sine wave (mean value response). Model 72-7745: displays true rms value. l Frequency response 40Hz~400Hz. C. Resistance Overload Range Resolution...

  • Page 28: Continuity Test

    Model 72-7740/72-7745: OPERATING MANUAL Accuracy Specifications (2) D Continuity Test Overload Range Resolution Accuracy Protection 1000Vp 400.0 Approximate 100 Remarks: l Buzzer beeps continuously. l Open circuit voltage approximate 0.45V. E. Diode Test Range Resolution Overload Protection Diode 1000Vp Remarks: l Open circuit voltage approximate 1.48V.

  • Page 29: Temperature

    Model 72-7740/72-7745: OPERATING MANUAL Accuracy Specifications (3) H.Temperature Overload Protection: Glass fuse 0.5A, 250V, fast type, 5x20mm. I. DC Current 400 A 0.1 A Glass fuse 0.5A, 250V, fast type Glass fuse, 5x20 mm. Glass fuse 10A, 250V, fast type Glass fuse, 5x20 mm.

  • Page 30: Ac Current

    Glass fuse, 5x20 mm. 10A, 250V, fast type Glass fuse, 5x20 mm. Remarks: Model 72-7740 : displays effective value of sine wave (mean value response). Model 72-7745 : displays true rms value. l 4A & 10A Range: For continuous measurement 10 seconds and interval not less than 15 minutes.

  • Page 31: Maintenance

    Model 72-7740/72-7745: OPERATING MANUAL MAINTENANCE This section provides basic maintenance information including battery and fuse replacement instruction. Warning Do not attempt to repair or service your Meter unless you are qualified to do so and have the relevant calibration, performance test, and service information.

  • Page 32: Replacing The Battery

    Model 72-7740/72-7745: OPERATING MANUAL l If the Meter beeps, the fuse is good. l If the display shows , replace the fuse and test again. l If the display shows any other value, have the Meter serviced and contact your dealer immediately.

  • Page 33: Replacing The Fuses

    Model 72-7740/72-7745: OPERATING MANUAL D. Replacing the Fuses (see figure 13) (figure 13) Warning To avoid electrical shock, arc blast, personal injury or damage to the Meter, use specified fuses ONLY in accordance with the following procedure. To replace the Meter’s fuse: Press the POWER to turn the Meter off and remove all connections from the terminals.
  • Page 34 Model 72-7740/72-7745: OPERATING MANUAL Rejoin the battery compartment and the case top, and reinstall the screw. 7. Rejoin the case bottom and case top, and reinstall the 2 screws and 2 rubber feet. Replacement of the fuses is seldom required. Burning of a fuse...

  • Page 35: Rs232C Port Cable

    Model 72-7740/72-7745: OPERATING MANUAL Te n m a Te s t E q u i p m e n t 4 0 5 S . P i o n e e r B l v d . S p r i n g b o r o , O h i o 4 5 0 6 6...

This manual is also suitable for:

72-7745

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