UNI-T UT39E+ 20000-Count True RMS Digital Multimeter: The Ultimate Guide

Overview

The UNI-T UT39E+ is the flagship model in UNI-T's upgraded UT39+ series, representing the pinnacle of professional-grade digital multimeters . Designed for advanced users, electronics engineers, and serious technicians, this meter combines exceptional 20000-count resolution, True RMS accuracy, and an unparalleled range of measurement functions in a rugged, reliable package .

Engineered to meet the rigorous demands of industrial, laboratory, and field environments, the UT39E+ boasts a remarkable 20000-count display—significantly higher resolution than standard 4000-count meters—enabling precise measurements for critical applications . With safety ratings of CAT II 1000V and CAT III 600V, it delivers professional-grade protection in high-energy electrical environments .

What truly sets the UT39E+ apart is its comprehensive feature set: True RMS for accurate non-linear load measurements, NCV (Non-Contact Voltage) detection, temperature measurement, frequency analysis up to 2MHz, capacitance up to 2000μF, transistor (hFE) testing, and a unique conductance (nS) function for measuring ultra-high resistance up to 10GΩ—making it the most versatile and capable model in the UT39+ series .

Key Features at a Glance

• Ultra-High 20000-Count Display: 4½ digit LCD with exceptional resolution for precision measurements—ideal for advanced diagnostics .

• True RMS Technology: Provides accurate readings even with non-linear or distorted AC waveforms, essential for modern electronics and variable frequency drives .

• Temperature Measurement: Built-in K-type thermocouple support for readings from -40°C to 1000°C (-40°F to 1832°F)—essential for HVAC/R and industrial process monitoring .

• Wide Voltage Range: Measures DC voltage up to 1000V and AC voltage up to 1000V with exceptional accuracy (DCV ±0.05%+3) .

• High Current Capacity: Measures DC/AC current up to 20A .

• Non-Contact Voltage (NCV) Detection: Dual-sensitivity mode (EFLo/EFHI) for safe live voltage identification without physical contact .

• Conductance Measurement: Unique 0.1~100nS range extends resistance measurement to 10MΩ~10GΩ—perfect for testing insulation and high-value resistors .

• Frequency Measurement: Up to 2MHz frequency testing capability for advanced signal analysis .

• Capacitance Measurement: Measures capacitance up to 2000μF (2mF) for testing motor start capacitors and power supply filtering .

• Transistor (hFE) Testing: Dedicated socket for testing NPN/PNP transistor current gain—valuable for electronics work .

• Comprehensive Testing: Includes resistance (up to 200MΩ), diode test, continuity test with acoustic indication, and duty cycle analysis .

• User-Friendly Features: Manual ranging with auto-ranging on select functions, data hold, backlit LCD, low battery indication, and auto power off .

• Rugged Construction: Durable protective holster with 1-meter drop protection—ideal for job site use .

• Safety Certified: CAT II 1000V / CAT III 600V with EN 61010 compliance .

Detailed Specifications

The UNI-T UT39E+ delivers professional-grade accuracy across an extensive range of electrical and temperature parameters .

Electrical & Temperature Measurement Specifications

General Characteristics

Special Functions

What's in the Box

Key Functions & Operation

1. True RMS AC Measurements

• Set the rotary switch to the appropriate AC function

• The True RMS technology ensures accurate readings even with distorted waveforms from variable frequency drives, switching power supplies, and non-linear loads .

• Essential for modern industrial and commercial electrical work

2. Ultra-High Resolution Display

• The 20000-count display provides exceptional resolution—up to 10 times higher than basic 2000-count meters .

• Enables precise measurements for critical applications, laboratory work, and component matching

3. Temperature Measurement

• Set the rotary switch to the temperature position

• Connect the included K-type thermocouple to the meter

• Place the temperature probe on or in the object being measured

• Range: -40°C to 1000°C for maximum versatility in HVAC/R, industrial process monitoring, and appliance repair 

4. NCV (Non-Contact Voltage) Detection

• Set the rotary switch to the NCV position

• Select sensitivity: EFLo (for ~110V) or EFHI (for ~220V) 

• Bring the top of the meter near a live conductor or outlet

• The meter provides audio and visual indication when AC voltage is detected

• Safety Benefit: Allows quick verification of live circuits before physical contact

5. Conductance Measurement (Unique Feature)

• Set the rotary switch to the nS position

• This function measures conductance in nanosiemens (0.1~100nS)

• Converts to resistance: 10MΩ to 10GΩ 

• Application: Ideal for measuring insulation resistance, high-value resistors, and leakage current—fills the gap where standard resistance ranges stop at 200MΩ 

6. DC/AC Voltage Measurement (Up to 1000V)

• Set the rotary switch to the appropriate voltage position

• Connect test leads in parallel to the circuit under test

• Measure up to 1000V DC or 1000V AC with exceptional accuracy (DCV ±0.05%+3) 

• Suitable for both low-voltage electronics and high-voltage industrial systems

7. DC/AC Current Measurement (Up to 20A)

• Set the rotary switch to the appropriate μA, mA, or A position based on expected current

• Connect test leads in series with the circuit

• The UT39E+ supports current measurement up to 20A 

• Dedicated input jacks for current ranges ensure safe operation

8. hFE Transistor Testing

• Set the rotary switch to the hFE position

• Insert the transistor into the dedicated hFE socket, matching the correct pinout (E, B, C) 

• Read the transistor's DC current gain (β) directly from the display (0~1000β)

• Application: Essential for electronics work, component matching, and circuit design

9. Frequency Measurement (Up to 2MHz)

• Set the rotary switch to the Hz position

• Connect test leads to the signal source

• Measure frequencies up to 2MHz 

• Perfect for signal generators, oscillators, and telecommunications work

10. Resistance Measurement (Up to 200MΩ)

• Set the rotary switch to the Ω position

• Connect test leads across the resistor

• Measures resistance up to 200MΩ 

• Ideal for testing high-value resistors, insulation, and sensor elements

11. Capacitance Measurement (Up to 2000μF)

• Set the rotary switch to the capacitance position

• Fully discharge capacitors before testing to avoid damage

• Connect test leads in parallel with the capacitor

• Measures up to 2000μF (2mF) —suitable for motor start capacitors and power supply filtering 

12. Continuity & Diode Testing

• Set the rotary switch to the continuity/diode position

• Continuity: Buzzer sounds when circuit is complete—ideal for quick wiring checks (0.01Ω resolution) 

• Diode Test: Displays forward voltage drop for semiconductor testing (0.001V resolution) 

13. Data Hold, Backlight & MAX/MIN

• Press HOLD to freeze the current reading on the display 

• Press and hold to turn the LCD backlight on/off 

• Use MAX/MIN to record and display peak values during measurement 

14. Auto Power Off

• Meter automatically shuts down after approximately 15 minutes of inactivity to save battery 

• Press any button or turn the rotary switch to wake

UT39E+ vs. UT39A+ vs. UT39C+

The UT39+ series offers three distinct models with specialized features, with the UT39E+ serving as the flagship :

Applications

The UNI-T UT39E+ is an ideal tool for:

⚡ Industrial & Power Distribution

• Troubleshooting control panels and machinery up to 1000V 

• Measuring current on industrial equipment up to 20A 

• True RMS accuracy for VFD and motor drive measurements 

• NCV detection for safe live wire identification 

🔧 Electronics Engineering & Repair

• Testing components with 20000-count precision—ideal for matching and selection 

• Measuring transistor gain (hFE) for circuit design 

• Frequency analysis up to 2MHz for signal processing work 

• Conductance function for measuring ultra-high resistance and leakage 

🌡️ HVAC/R & Refrigeration

• Measuring vent temperatures, superheat, and subcooling with the included thermocouple 

• Troubleshooting furnaces, air conditioners, and refrigeration systems

• Testing thermostats, sensors, and control boards

• Checking start/run capacitors up to 2000μF 

🏭 Laboratory & Educational

• Ideal for university labs and advanced electronics courses 

• High-resolution measurements for research and development

• Teaching advanced measurement techniques with professional-grade equipment

• Conductance function for physics experiments and material testing

🚗 Automotive Diagnostics

• Testing car battery voltage (12V/24V systems)

• Checking alternator output and charging systems

• Measuring parasitic drain with high resolution

• Temperature monitoring of engine components (with thermocouple)

🔬 Specialized Applications

• Insulation testing: Conductance mode measures up to 10GΩ 

• Petroleum and chemical industry: CAT III 600V safety for hazardous environments 

• Aerospace and marine: High-precision measurements for critical systems 

• Research facilities: 20000-count resolution for detailed analysis

Safety Features

The UT39E+ incorporates multiple advanced safety features to protect users :

• CAT II 1000V / CAT III 600V Rating: Suitable for measurements on distribution circuits and permanently installed equipment

• Smart Anti-Burn Design: Built-in protection against misconnection and overloads

• Overvoltage and Overcurrent Alarm: Triggers during faulty operation to alert user

• NCV Detection: Allows safe voltage checking without physical contact

• 1-Meter Drop Protection: Withstands accidental falls with protective holster 

• Low Battery Indication: Alerts user when batteries need replacement to maintain accuracy

• Fused Current Inputs: Protection on all current ranges

Customer Reviews Summary

Users consistently praise the UT39E+ for:

• Precision: "High precision and functionality, especially in resistance measurements" — Verified users 

• Build Quality: "Прорезиненный корпус и интуитивно понятное управление делают работу с прибором удобной" (Rubberized body and intuitive controls make operation convenient) — Russian review 

• Value: "性价比极高...提供了几乎相同的性能，但价格更加亲民" (Excellent price-performance ratio... provides almost the same performance at a more accessible price) — Verified buyer 

• Durability: The 3mm protective holster and 1-meter drop protection inspire confidence on job sites 

• Conductance Function: Unique feature highly valued by engineers for insulation testing 

Minor Considerations:

• No separate power button—on/off controlled by rotary switch only 

• Backlight timer fixed at 30 seconds (non-adjustable) 

• Slightly larger than pocket meters due to advanced features

Why Choose the UNI-T UT39E+?

The UT39E+ stands out as a professional-grade, feature-complete multimeter that delivers exceptional performance for advanced users.

Key Differentiators:

Final Verdict

The UNI-T UT39E+ is the definitive choice for professionals who demand the absolute best in portable measurement technology. Its 20000-count True RMS accuracy, comprehensive feature set (including the unique conductance function), and professional-grade safety certifications make it the ultimate tool for electronics engineers, industrial electricians, and serious technicians