Thanks to John for sending me some of the new updated versions of the Koppla charger. Since reviewing that one six years ago I've had one plugged in 24/7 for charging all my USB items, and it has performed flawlessly.
The supply voltage range has been widened to 100V - 240V and the output remains the same at 3.4A total at 5V with a maximum of 2.4A per socket. This charger doesn't offer higher voltage express charging, which is good news for your phone's battery.
I desoldered the mystery capacitor between the main MOSFET's gate and drain, and it measured around 22pF, which makes more sense.
The main circuitry changes are an unusual feature that shuts off the startup circuitry to reduce standby power and a synchronous rectifier to improve efficiency greatly. Each output has its own self resetting overcurrent protection.
The little MOSFET for shutting off the startup resistors is probably a depletion MOSFET that is on by default and turned off by a control voltage.
The transformer is wound in four layers. Primary, secondary, more primary and feedback. The secondary insulation, spacing and sleeving is good.
In the video I mentioned Apple compatibility, but the restrictive nature of status brands like Samsung and Apple does not guarantee compatibility. This industry-standard charger should charge just about every other brand in the known universe though.
IKEA are one of my recommended sources for USB chargers, as they comply fully with safety regulations while being extremely affordable. It's very important to use a good quality charger for your devices to protect them and yourself against damage/shock.
It's also best to use prominently branded cables too, especially for devices that charge at higher currents.
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