AstroAI Digital Multimeter, TRMS 4000 Counts Volt Meter (Manual and Auto Ranging); Measures Voltage Tester, Current, Resistance, Continuity, Frequency; Tests Diodes, Temperature (Red)

Great value. This is a really nice, high-quality auto-range multimeter. Comes with a battery installed and all ready to go. Nice, tough case. Good switch. Cheap and good!

Mi esposo lo amo, fue un buen regalo cumple muy bien su funcion en su trabajo lo amamos

Buenos precio y muy confiables

After an intense review of what was available in the digital multi-meter (DMM) product space, I purchased four AstroAI TRMS 4000 meters based on competitive pricing with similar products with similar specifications. These multi-meters were purchased for use by middle and high school students that are participating in the National Science Olympiad program. The features that were required were simple to use, has an easy to read display, is both precise and has acceptable uncertainty, in a physical package that could withstand the abuse/misuse of the students.Most of the digital multi-meters in this same price category, as the TRMS 4000 were NOT auto ranging or too small to have a reasonable size display. The meters with similar features by Fluke, Extech and Amprobe, to name a few, varied in price from ten to twice as expensive. Since I needed four, all of those meters were immediately ruled out. When the TRMS 4000 meter arrived, a quick physical, hands on inspection, revealed a solid design that was well labeled, with an LCD display that was about the same size as my personal hand held Fluke DMM.To test the meters, I used a variety of batteries and precision one-percent resistors to compare the performance of each meter, against my Fluke and against each other. In all cases the TRMS 4000 meters within +/- 4 least significant digits in the three and a half digit mode and +/- 2 least significant digits in the three digit mode. Without doing any real statistical analysis and without true NIST traceable standards, I feel comfortable that these meters were precise with an uncertainty that was within 1% +/- 1 digit in the tested ranges, which seems to correlate well with AstroAI’s stated specification. I should note that the results I obtained with precision resistors was well within the stated specifications.Since these we to be used for Science Olympiad competition, and the general rules prohibit using dangerous voltages, I did not test the AC or higher DC voltage ranges. However seeing the excellent results with low voltage DC and resistance, I would feel comfortable using one of these as troubleshooting tool in a professional capacity on low frequency equipment and appliances. Because TRMS 4000 has a specified input impedance of 10 Meg Ohms, I would not recommend this for use on sensitive instrumentation or high frequency circuits where test input impedances > 100 Meg are recommended and generally required. I would also recommend not using any hand-held multimeter for directly measuring currents in excess of 1 amp even though they may be equipped to do so, external shuts should be used for these types of measurements.In summary, for the price, this is an excellent choice for the serious hobbyist and student. If I had it to do over, I would still purchase these DMMs.

I was initially looking at the 6000 count meter but the comment on Amazon just below the picture said there was a newer version so I clicked on that link. A friend (electrical type) told me I should have stuck with my first choice.This meter is more than enough for what I will be using it for as a DIY "don't-wannabe-electrician" - I'll leave that for the professionals. After receiving the meter I started to investigate some of the "buzz" words that I encountered in the various product reviews and had I done this before buying, I would have stuck with this unit's older brother. To that end I would suggest that any entry-level person looking for a budget meter at least read up on the various CAT (II,III,IV,etc.) ratings and what they represent to at least be aware of some potential hazards.I stuck with the DT132A (4000 counts) because of all the positive reviews and the price. The next model up is only about $15 more but I would have found comfort in the higher CAT ratings although I don't intend on venturing into that territory.I was "middle of the road" on the accuracy rating simply because I have no experience to grade against. I applaud the company's customer service as they contacted me right off and asked that I call them before returning the meter if I had any problems. First, I thought the thermocouple was faulty and they offered to send me a replacement (it was operator error). Then I found the battery cover screw had been severely over-tightened and the head stripped. They provided me with the screw size which I have already replaced and without "dinging" them on the rating. I easily located a full size version of the product manual - the one that came with unit is small and hard to read. I don't anticipate calling their customer service again but I am confident they will respond promptly.For the price and for what I will be using it for I am satisfied with my purchase. There are many budget meters on the market but I have zero knowledge on the specific needs of the buyers - only my intended purposes - so I had to rely on the various reviews that I read.