Deadly 3-USB Charger (test, teardown, schematic, oscilloscope measurements)
Today I took a look at a Chinese 5V 1A USB charger with 3 USB ports. I tested the maximum current capability, took a look inside, reverse engineered the schematic of it, measured some waveforms using my oscilloscopes and finally I made an autopsy of the switching transformer. This power supply from China from Ebay turned out to be a death trap. It's dangerous because of a too narrow isolation on the board and virtually no isolation in the transformer. The USB output and thus your phone or other device may easily become live at mains voltage, leading to an electric shock. Having no fuse, it also poses a fire hazard.
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