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MPK-257 Digital Very Low Resistance Ohmmeter

The MPK-257 is a portable, microprocessor-controlled very low resistance ohmmeter designed for precise testing of switches, circuit breaker contacts, transformer and motor windings, wire and cable samples, and busbar joints. With test currents from 1 mA to 10 A, the MPK-257 offers high accuracy and resolution for laboratory and field applications.

Using the four-terminal Kelvin method, the MPK-257 eliminates errors caused by test leads and contact resistances. Measurements are displayed on a digital alphanumeric display with up to 4½ digits resolution, with a best resolution of 0.1 μΩ. With selectable test ranges up to 2,000 Ω, the instrument ensures flexibility for a wide variety of applications.

The MPK-257 incorporates USB connectivity for data transfer and analysis, as well as robust protection against inductive voltage peaks. Lightweight, impact-resistant, and IP65-rated, it is suitable for use under severe environmental conditions while delivering laboratory-grade precision.

Function

• Very low resistance measurement with test currents from 1 mA to 10 A
• Four-terminal Kelvin method eliminates lead resistance errors
• Resistance measurement up to 2,000 Ω with resolution down to 0.1 μΩ
• Automatic direct digital display with 4½ digits resolution
• USB interface for data transfer and analysis
• Built-in rechargeable battery for field portability
• Rugged IP65-rated housing for use in harsh environments
• Accurate, offset-free signal amplification with long-term stability

Technical Specifications

test currents

  • 1 mA, 10 mA, 100 mA, 1 A, 5 A, 10 A

  • Continuously adjustable from 0 to 100%

resistance ranges

  • 0–200 mΩ @ 10 A

  • 0–1000 mΩ @ 5 A

  • 0–200 mΩ @ 1 A

  • 0–2000 mΩ @ 100 mA

  • 0–20 Ω @ 10 mA

  • 0–2000 Ω @ 1 mA

resolution

  • 0.1 μΩ @ 10 A

output voltage

  • Up to 10 V DC open circuit (depending on current)

measurement principle

  • Four-terminal, Kelvin-type

accuracy

  • ±0.10 % of reading + 3 ULSD (Units of Least Significant Digit)

display

  • Alphanumeric, 4½ digits resolution

interface

  • USB for serial data output

  • Compatible with T-Logger software for analysis and reporting

protection

  • Effective protection against voltage peaks from inductive loads

environmental protection

  • IP65 (with closed lid)

safety compliance

  • IEC 61010-1

power supply

  • Rechargeable LFP battery 12 V, 6000 mAh

  • 100–240 V AC mains

  • Auxiliary 12 V supply input

  • Built-in battery charger

operating conditions

  • Temperature: -10 °C to +50 °C

  • Humidity: 95 % RH (non-condensing)

storage conditions

  • Temperature: -25 °C to +70 °C

dimensions

  • 378 × 308 × 175 mm

weight

  • ~6.5 kg

Key Features

  • Resolution as fine as 0.1 μΩ

  • Resistance measurement up to 2000 Ω

  • Six selectable test currents up to 10 A

  • USB interface for data transfer

  • Rugged portable design with rechargeable battery

  • Protection against inductive voltage peaks

  • IP65 environmental rating for harsh field conditions

Standard Accessories

  • 2 combined current and potential leads

  • Ground cable

  • Temperature sensor

  • Power cord

  • Auxiliary 12 V external power cord

  • USB cable

  • User guide

  • Carrying bag

  • T-Logger software

  • Tentech Remote Control app

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