Integrated True RMS Digital AC DC Clamp Meter & Multimerter 2138R

•  Ideal electrical tool for professionals
•  True RMS measurements of AC voltage and current
•  Integrated with digital multimeter
• Very nice touch on the case made of thermoplastic elastomeric rubber
• Excellent smooth rotary switches
• Secondary injection molding case
•  Max voltage: CAT II 1000 V and CAT III 600 V
•  Max current: 1000 A AC/DC
•  Max. jaw opening gap: Ф42 mm
•  Comply with: IEC1010-1 & IEC1010-1-032 standard
•  Double insulation: Protection class 600V CAT III
•  Display: both 3999 counts digital numbers and 40 segments bar graph
•  AC / DC voltage measurement
•  AC / DC current measurement
•  Resistance, diode, frequency measurement
•  Continuity audio alert
•  Auto range
• Auto power off
• Zero reset button for DC AC current measurement
• Data hold, Max, Min and Relative functions
•  Back light of LCD panel
• Clamp jaw light
• Battery low indication  
• High quality and reliable

Technical details

Package includes

1. True RMS digital AC DC clamp meter 2138R
2. Red and black test leads (part silicon)
3. User manual
4. Batteries
5. Carry bag

Referential information

When measuring the value of an alternating current signal it is often necessary to convert the signal into a direct current signal of equivalent value (known as the RMS, root mean square, value). This process can be quite complex. Most low cost instrumentation and signal converters (for example handheld multimeters of the sort used by maintenance engineers) carry out this conversion by filtering the signal into an average value and applying a correction factor.

The value of the correction factor applied is only correct if the input signal is sinusoidal. The true RMS value is actually proportional to the square-root of the average of the square of the curve, and not to the average of the absolute value of the curve. For any given waveform, the ratio of these two averages will be constant and, as most measurements are carried out on what are (nominally) sine waves, the correction factor assumes this waveform; but any distortion or offsets will lead to errors. Although in most cases this produces adequate results, a correct conversion or the measurement of non sine wave values, requires a more complex and costly converter, known as a True RMS converter.