AT35 USB 3.0 Tester Power Meter 3.7-30V 0-4A Voltage Tester Multimeter Current Meter Tester Detector IPS Color Display Voltmeter Ammeter, USB Capacity Power Charger,Upgraded Version

I am working on very low power IoT devices and I wanted an easy way to get a ball park measurement for how much power was being used without hooking up an oscilloscope or other equipment. I compared the measured power consumption against the o-scope and got 9.39ma versus the 9ma shown by this unit. It is close enough for me to use it as way to judge whether code changes improve the deep sleep current drain.This is a great tool if you want to quickly check current draw by a USB device.

I have not had a lot of time to test and use this. I have used it a few times and it was dead on perfect in its reading. I have to figure that it will stay this way. It comes with the device in a nice small storage case. This case is a nice touch as it will keep dust and other foreign objects from getting in and on it.Operation is simple. (Once you find the buttons.) It is very bright and can be seen anywhere you use it. So far so good. If I experience any troubles i will update this review to reflect them. But I do not think that is going to happen.

~ I need... This little gem is very accurate while I was testing it with other USB testers, on capacity & load draw. The other fine things on this is... it's ability to inform you of what type of fast charge protocol your device is using. Temperature of charger & screen rotation to mention a few. What it is missing is a timer, which I am accustomed to. Where the clock will stop, showing you how many hours when the battery or device stopped taking in a charge. Display could be abit larger, I find myself breaking out the magnifying glass to read the smaller text. Perhaps in the next version this will be done.

I would have loved to have given this 5 stars because it's really accurate and it provides all the information you would need on a USB port. The Display while Bright and clear has an issue with some of the values being so small that only younger people will be able to read them clearly. I had to really get up close to see some of the Values. Luckily the Most important stuff is easy to read.

Glad i bought this. I found 2 adapter that was an out rite lie rated at 2 amp only doing 1 amp or less straight to the garbage they went.In short if you have an adapter that is taking a long time to charge something test it with this to see the output when the battery is dead many companies will over rate an item 2 amp you can expect 1.7 amp or better and watch the voltage sag if it less than 4.5 volts at full load toss it in the garbage. i had one rated at 2 amp and it was 3.97 volts @ 1.1 amp total garbage. The other barely 1 amp @ 4.9 volts garbage it went. Folks with todays tech stuff you need at least 2 amp and a stable voltage to get the phones and tablets charged in a timely manner and have enough reserve power to still use the devise.The battery in the devises is 4.2 volts and charging 5 volts in gets regulated at 4.2 if there is a bad voltage sag it takes even longer to charge. Im getting one 2.4 amp amazon basics adapter to see how it works to replace the 2 that i tossed out. If it does what its suppose to i may buy another one if not ill send it back but ill post a review on it as well.

The media could not be loaded.  Nice display that is very easy to read. It works well, does what I wanted and I'm happy.Testing USB devices, USB power supplies, Powerbanks, and USB ports was easy and accurate.

I bought this item to see if my cables are carrying enough amperage, it lets me know which charging cables work better than others.It also showed me that when a charger could not deliver the full 5 volts that the amperage dropped. When this happens the PHONE is detecting the charger is not working correctly, so the PHONE chooses to demand less amperage therefore voltage going back to normal but charging is now slower.

This is unusable for what I bought it for - testing full load on raspberry pi computers with GPIO in use. This seems to restrict devices to 1 amp, but the description says up to 4 amp.

Would like a larger watts display as that is a more accurate measure of charging power (volts x amps = watts). Good enough to test a few USB charges a throw out the old 5 watt chargers as no longer useful.