UNI-T UT55 Digital Multimeter, 1000 V DC, 20 A, 200 MΩ, Temperature Measurement

UNI-T UT55 Digital Multimeter, 1000 V DC, 20 A, 200 MΩ, Temperature Measurement

The UNI-T UT55 is a manual-ranging digital multimeter designed for general electrical and electronic measurements, component testing and maintenance work. It measures AC/DC voltage and current, resistance, capacitance, frequency and temperature, and also provides diode, continuity and NPN/PNP transistor hFE testing. Its 3½-digit LCD provides up to 1999 counts, while automatic power-off helps reduce battery consumption.

Key specifications:
1000 V DC • 750 V AC • 20 A AC/DC • 200 MΩ • 20 µF • −20…1000 °C • 1999 counts

Key features

• Multiple electrical measurements – measures AC/DC voltage, AC/DC current and resistance with one instrument.
• Capacitance measurement up to 20 µF – useful for checking capacitors and electronic components.
• Temperature measurement from −20 to 1000 °C – UT55 supports thermocouple temperature measurement.
• Frequency measurement up to 20 kHz – suitable for checking lower-frequency electrical and electronic signals.
• Transistor hFE test – built-in socket supports NPN and PNP transistor gain measurements over a 0–1000 β display range.
• Diode and audible continuity testing – enables quick testing of diodes, wiring and electrical connections; the buzzer operates at approximately ≤70 Ω.
• 1999-count LCD – 3½-digit display provides clear measurement readings.
• Automatic power-off – reduces consumption of the 9 V battery when the meter is left unused.
• Manual range selection – allows the required function and measuring range to be selected directly.
• Tilting stand – provides convenient display viewing during bench work.

Applications

The UNI-T UT55 is suitable for household electrical troubleshooting, electronics work, education, laboratory use and general technical maintenance.

It can be used to check supply voltages, circuit current and continuity, resistors, capacitors, diodes, transistors, signal frequency and temperature.

Compatibility and limitations

• Measurement ranges are selected manually.
• AC voltage and current measurements are not True RMS. The instrument measures average value and is calibrated to display the RMS value of a sine wave; a True RMS instrument is preferable for strongly distorted AC waveforms.
• The 20 A range is intended for short-duration measurements only. The manufacturer's manual specifies a maximum measurement time of 15 seconds, followed by at least a 15-minute interval.
• The 20 A input is not fuse protected.
• Maximum frequency measurement range: 20 kHz.
• Maximum capacitance measurement range: 20 µF.
• The instrument is intended for indoor use.

Technical specifications

Parameter	Specification
Instrument type	Digital multimeter
Ranging	Manual
Display	LCD, 3½ digit
Maximum display	1999
DC voltage	200 mV / 2 V / 20 V / 200 V / 1000 V
DC voltage resolution	100 µV / 1 mV / 10 mV / 100 mV / 1 V
Best DC voltage accuracy	±(0.5% of reading + 1 digit)
AC voltage	2 V / 20 V / 200 V / 750 V
Best AC voltage accuracy	±(0.8% of reading + 3 digits)
AC voltage frequency range	40–400 Hz
AC measurement method	Average responding, calibrated to RMS of a sine wave
DC voltage input impedance	10 MΩ
DC current	2 mA / 20 mA / 200 mA / 20 A
Best DC current accuracy	±(0.8% of reading + 1 digit)
AC current	20 mA / 200 mA / 20 A
Best AC current accuracy	±(1% of reading + 3 digits)
Maximum current	20 A
20 A measurement duration	≤15 s; at least 15 min interval
Resistance	200 Ω / 2 kΩ / 20 kΩ / 200 kΩ / 2 MΩ / 20 MΩ / 200 MΩ
Resistance resolution	0.1 Ω / 1 Ω / 10 Ω / 100 Ω / 1 kΩ / 10 kΩ / 100 kΩ
Capacitance	2 nF / 20 nF / 200 nF / 2 µF / 20 µF
Capacitance resolution	1 pF / 10 pF / 100 pF / 1 nF / 10 nF
Capacitance accuracy	±(4% of reading + 3 digits)
Frequency	Up to 20 kHz
20 kHz range resolution	10 Hz
Best frequency accuracy	±(1.5% of reading + 5 digits)
Frequency input sensitivity	Approx. 100 mVrms
Temperature	−20…1000 °C
Temperature resolution	1 °C
Temperature accuracy −20…0 °C	±(5% + 3 digits)
Temperature accuracy 0…400 °C	±(1% + 3 digits)
Temperature accuracy 400…1000 °C	±2%
Diode test	Yes; test current approx. 1 mA
Continuity test	Audible buzzer at approx. R ≤70 Ω
Transistor test	NPN / PNP hFE, 0–1000 β
Automatic power-off	Yes
Low-battery indication	Yes
Power supply	1 × 9 V battery, NEDA 1604 / 6F22 / 006P
Operating temperature	0…40 °C
Storage temperature	−10…50 °C
Operating altitude	Up to 2000 m
Relative humidity	Up to 80% at ≤31 °C, decreasing to 50% at 40 °C
Safety standard	IEC 61010
Measurement categories	CAT I 1000 V / CAT II 600 V / CAT III 300 V
Pollution degree	2
Insulation	Double insulation
Dimensions	190 × 88 × 34 mm
Weight	Approx. 270 g meter only; approx. 550 g with holster and tilt stand

Accuracy note: manufacturer accuracy specifications apply for one year after calibration at 23 ±5 °C and relative humidity below 75%. Accuracy is expressed as ±(% of reading + digits).

Construction and controls

The UT55 uses a rotary function/range selector and provides dedicated input connections for measurement, capacitance, temperature and transistor testing. LCD digit height is approximately 27 mm. The folding stand allows the display to be viewed conveniently at different angles.

Important operating and safety information

• Do not exceed the maximum rating of the selected range or input.
• Extra caution is required when working above 60 V DC or 30 Vrms AC.
• Disconnect circuit power before resistance, capacitance, diode or continuity measurements; discharge capacitors before capacitance testing.
• Do not change the rotary switch position while measuring voltage or current.
• Current ranges up to 200 mA are protected by a 315 mA / 250 V fast-acting 5 × 20 mm fuse; the 20 A range is not fused.
• Use the instrument only when the meter and test leads are undamaged.

Package contents

• UNI-T UT55 digital multimeter
• Pair of test leads
• WRN-01B temperature thermocouple