UNI-TDigital Multimeter Tester UT139C, Voltage Meter Tester Capacitance Meter Frequency TRMS 6000 Counts Auto/Manual Ranging

This is a somewhat specialized DVM (Digital Volt Meter) in that it measures AC Voltages and Currents using a true RMS circuit and has a transistor test function. True RMS matters for distorted waveforms such as with iron core transformer currents and in audio signals - Which would only apply to an electronic technician or engineer. An electrician would not need the true RMS feature. And of course only an electronic technician or engineer would be measuring transistor gain (Hfe or Beta).This is a pretty good value if you are an electronic technician, engineer, or hobbyist. A name brand like Fluke would cost much more for the same functionality and specifications. You can check out the spec sheet online.Here are some additional measurement notes based on my instrument not mentioned in the specifications:Measuring a silicon diode in the diode function, the measurement current is about 0.90 mA.Measuring continuity in the continuity function, the measurement into a short is about 0.25 mA.Measuring an LED in the LED function, the measurement current is around 4 mA - which is enough to see the actual LED under test light up.Measuring the Beta of an NPN transistor, the base measurement current is around 5 uA (Beta = Ic/Ib).Measuring a resistance, on the lowest scale the measuring current into a short is about 0.25 mA.The backlight operation of the display is a little odd at first. When you turn on the meter it is in backlight mode but it won't come on except in the dark or if you put your hand temporarily over the display to darken the built in light sensor - Then the backlight stays on until you turn it off either by shutting off the meter or using the backlight off button. At first I thought my backlight was defective until I discovered how to make it turn on. I would have preferred the backlight button just turn on or off the backlight without the ambient light sensor in the meter.The light built into the back of the meter that turns on by holding a button is a pretty nice idea if you are working in dark.The "delta" function is useful when measuring low resistances to account for test lead resistance or measuring low capacitance in the 10's of pF.Being able to measure AC or DC Voltages up to 1000 V is useful if you work with higher power vacuum tube equipment.The only negatives apparent to me are:(1) The meter took 16 days to get from China to my home in the USA, but it was within the promised delivery date.(2) The instructions recommend against measuring full scale currents for more than a minute - That is odd to me. Either the current sensing resistor isn't rated for continuous power at 20 Amps or it heats up and makes the measurement inaccurate. That was not a measurement I was planning on, but it's decidedly "odd".All in all, the meter seems to be well made and generally well designed. The probes seem to be of good quality. If you need the functions this meter has and are on a modest budget, then this is a good choice.To be honest, if I were only going to use it as a general electrician might for a job, I'd spend the extra money on a Fluke because of their reliability and ruggedness. But as a hobbyist mostly working on home electronics, this is a very good value.

Very nice meter. I did not everything I would use the NCV feature on this meter but had to change a tankless hot water heater and wanted to make sure that power was actually off. Just held the meter to the the wire going to the unit and verified it was off. No reason to use the leads. Also noticed this works with USB cords as well to see if they have power at the end. I also work on analog power supplies which will have large capacitors on them. This unit is able to measure these which my old meter would not. So far I am very pleased with this meter.

Tested accurate as can be for the price. Solid build quality and good reviews online. Haven’t used the BT feature yet. Couldn’t find a case that I didn’t want to risk not fitting and having to return on Amazon so ordered from that “express” site.Unit came with everything needed to get started. Worth the price for the hobbyist or other mid-level usages.

Good product, meets the conditions that it specifies, comes with the pair of voltage measurement probes and others, and also the temperature ones. something to highlight the packaging, I get a little damaged the box, but rest well

There is a lot to choose from when you get away from the big names in meters. This brand, and meter in particular, was a pleasant surprise. I love the soft touch controls, bright display, and ring out tone you can easily hear, and overall great quality build of this meter. Very solid in build. The ONLY thing I'd suggest is getting a better set of leads. With these silver tipped leads, the response time on continuity is a little slow. I added my gold tipped leads and it's almost instantaneous with response in continuity. It's not the meters fault, and common in any meter with cheaper leads.....which most come with now. Just figure on spending a few dollars extra for a nicer set of leads and this meter will fly. I love it!

Excellent device, was looking to purchase one long time. This is the best for its price and functionality.

I purchased the UT890D+ multimeter in June 2024. Now I am running into an issue with DC voltage measurements, the meter constantly shows a negative residual voltage instead of zero (as shown in the attached picture). This residual reading affects the reading when measuring the actual DC voltage. There is no means to reset the meter.

Excelente, mucha calidad!