• AC/DC voltage range: 0.01mV to 1000V
  • AC/DC current range: 0.01µA to 20A
  • Resistance range: 0.01Ω to 40MΩ
  • Capacitance range: 0.001nF to 40mF
  • Frequency (electrical) range: 40Hz to 400Hz
  • Frequency (electronic) range: 0.001Hz to 100MHz
  • Temperature range: -50 to 1382°F
  • Basic accuracy: ±0.06%
  • Diode open circuit voltage of 2.8V DC
  • MIN/MAX/Relative/Data Hold
  • Double molded for waterproof protection (IP67)
  • CAT IV-600V safety rating for industrial applications
  • Case and basic accessories included

What's in the Box

  • Double molded test leads
  • Remote receiver with USB cable
  • Magnetic hanging strap
  • Type K bead wire
  • Temperature probe
  • 9V battery
  • Software
  • Carrying case


The Extech EX540/EX542 is an industrial quality True RMS multimeter featuring 1000V input protection over all ranges. The EX540/EX542 was designed to handle the rigors of field testing in adverse conditions including drop-tests from 6 feet as well as double molded housing for waterproof protection to IP67 standards. The EX540/EX542 also includes a CAT-IV-600V safety rating for industrial applications and a 9,999 reading data logger that allows users to store data for later retrieval.

The Extech EX540/EX542 is a versatile instrument capable of accurately measuring AC/DC voltage, AC/DC current, resistance, frequency, capacitance, and temperature. The basic accuracy of the meter is ±0.06%. Results are displayed on a large, 40,000-count LCD for the highest resolution. The EX540/EX542 has a data acquisition mode for real-time transmission to your PC via a wireless USB interface. The EX540 transmits at 915MHz and the EX542 transmits at 433MHz.

Additional features of the Extech EX540/EX542 include: diode and continuity tests, MIN/MAX, Data Hold and Relative, an auto power off with disable feature, and dual sensitivity frequency functions (electrical/electronic).



Test Leads

Current Clamps


Please consider these optional accessories.


This product can be used in the following applications: