Electronics and technology blog    /    Materials for July 2018 year

Somehow, despite the large number of reviews I've written, I've hardly ever reviewed devices related to audio equipment in one way or another. Of course, I did review a power supply for a power amplifier, but in my view that's only tangentially related. So I've decided to take a look at amplifiers, DACs, and other audio devices, starting with a volume controller. I chose this volume controller mainly for aesthetic reasons, since it's very simple in terms of functionality, so today's review won't be very long.

Standalone devices that support Quick Charge are becoming increasingly common, so I decided to take a closer look at what “feeds” these “pets”—a QC 3.0 charger (power supply). It’s very compact, but you can read all about it in the review: as usual, I’ll take a look, run some tests, take it apart, and share my conclusions.

I've published quite a few battery reviews, and people often asked why I don't measure the batteries' internal resistance in them. My answer was usually the same: the instruments I had couldn't measure this parameter accurately, so there was no point in taking measurements. But fairly recently, I got my hands on a specialized instrument designed specifically for this kind of measurement. This device belongs to a very specialized class of measuring instruments, but I can imagine it being useful for more than just working with batteries.

How many times have I started with the words, “I’ve already reviewed a similar product,” only to find myself doing it again. About a year and a half ago, I posted a review of a somewhat unusual power bank for four 18650 batteries, with independent charging and pass-through power. Today’s review is of a very similar device, though with a few differences.

Some time ago, a friend of mine who works with various batteries asked me to come up with a test bench for battery packs. One of the bench’s key functions would be discharging them. At first, I planned to build everything myself, but it turned out that China sells an inexpensive, decent kit for the job, and in some situations it makes more sense to use it than to start from scratch.

GearBest is holding a sale on one of its popular TV box models, and as far as I can tell, this is currently the lowest price.

Another power supply has landed in my hands. I didn't buy it; a friend of mine did, but that doesn't matter here. What caught my attention first was its claimed output of 400 W, its fairly compact size, and the fact that it has power factor correction.

As it happens, there are currently two leaders in the video surveillance industry. I’ve written quite a bit about one of them, the well-known company Hikvision. But the other company has somehow remained in the shadows. Although its name, Dahua, may not sound particularly appealing to Russian speakers, it would still be wrong to overlook it. I don’t know why, but there are noticeably fewer reviews of this company’s products, and that’s partly why I decided to fill the gap. Besides, I’ve been asked about Dahua products several times already. So today I’m reviewing and briefly comparing products from two major companies.