Klein MM400 vs MM420 Multimeters – What’s the difference?

In this post we compare two similar multimeters from Klein Tools.

This article will delve into a comparative analysis of these two models, examining their technical specifications, usability, and functionality to help you make an informed decision.

Overall, the Klein MM420 has some advantages over the MM400 by way of capacitance measurement limit, True RMS and Duty cycle measurements.

The article also explains in what situations you would need these enhancements.

Klein Tools MM400 Multimeter, Digital Auto Ranging, AC/DC Voltage, Current, Capacitance, Frequency, Duty-Cycle, Diode, Continuity, Temp 600V

Comparison Table

Here is a comparison table highlighting the key features and differences between the Klein MM400 and Klein MM420 multimeters:

FeatureKlein MM400Klein MM420
šŸ’³ Cost Check PriceCheck Price
Basic Accuracy (DC Voltage)Ā±0.5%Ā±0.5%
Voltage Range (AC/DC)Up to 600VUp to 600V
Current Range (AC/DC)Up to 10AUp to 10A
True RMSNoYes āœ…
ResistanceUp to 40 MĪ©Up to 40 MĪ©
CapacitanceUp to 100 ĀµF to 200 ĀµFUp to 200 ĀµF to 2000 ĀµF āœ…
Temperature MeasurementYes, with thermocouple includedYes, with thermocouple included
Frequency/Duty CycleFrequency onlyFrequency and Duty Cycle āœ…
Display4000 count LCD4000 count LCD
Safety RatingCAT III 600VCAT III 600V

Both models share several features but the Klein MM420 offers enhancements in capacitance measurement range and includes duty cycle measurements along with frequency, positioning it as a slightly more advanced tool suitable for more varied electrical tasks.

Klein Tools MM420 Digital Multimeter, Auto-Ranging TRMS Multimeter, 600V AC/DC Voltage, 10A AC/DC Current, 50 MOhms Resistance

Overview of Differences

  1. Capacitance Measurement: The MM420 offers an expanded capacitance measurement range (up to 2000 ĀµF) compared to the MM400 (up to 200 ĀµF), making it more suitable for applications involving larger capacitors.
  2. Frequency and Duty Cycle: While both models measure frequency, the MM420 also measures duty cycle, an additional feature that can be crucial for diagnosing and troubleshooting electronic circuits.
  3. True RMS: The MM420 includes True RMS (Root Mean Square) measurement for more accurate readings of non-linear loads, a feature not available in the MM400.

These enhancements make the MM420 a slightly more advanced tool, ideal for users needing extra capabilities for complex diagnostics in electrical and electronic environments.

Klein Tools MM420 Digital Multimeter, Auto-Ranging TRMS Multimeter, 600V AC/DC Voltage, 10A AC/DC Current, 50 MOhms Resistance