Cheap USB charger teardown

Here is teardown of another cheap USB charger bought some time ago for around two euros from some chinese online shop. Brand “Designed by Able” Model 1300.

Label

Circuit board

Closeup of circuit board

One finding is that rectifier is replaced with diode, meaning that this half-wave rectifies mains power.

Other findings:

- The switcher circuit is based on two transistors (SW 13003 and UTC S8030) and optiosolator feedback

- There does not seem to be any fuse (or fusible resistor or other protection component) anywhere, the mains power is directly rectified with 1N4007 diode to main capactor

- The insulation distances between promary and secondary on the circuit board are quite small: shortest distance around 3 mm from solder to solder and slightly over 2 mm track-to-track

I don’t don’t thinks this is safe or good quality power supply. It might not be immediately dangerous, but the safely level is very low -I quess that this might not get though all the electrical safety regulations if gets tested by regulators.

If you need USB power supply, get something safer.

59 Comments

  1. Tomi Engdahl says:

    Tähän aiheeseen löyhästi liittyen: katsokaa juutuubista riemastuttavan tsekin “DiodeGoneWild”in videoita aiheesta vaaralliset USB-laturit. Hän on bongaillut noita Y-konkkia monen näköisiä, yleensä siellä on tavallinen muutaman nanon, kilovoltin konkka, joka ei täytä minkään valtakunnan (venäjän ehkä) turvamääräyksiä.

    Reply
  2. Tomi Engdahl says:

    Dangerous USB phone chargers 15
    https://www.youtube.com/watch?v=11viSmS9WWc

    A pair of small 5V 1A USB chargers, what’s inside, checking the safety, interference and quality. The first one was a part of handheld oscilloscope accessories, the second one is from eBay. Let’s see what surprises are hidden inside of them. Some chargers may not comply with safety regulations, cause an electric shock or fire. Their current rating may be fake, the output voltage may be wrong and they can cause electromagnetic interference (EMI) or damage your USB devices.

    Reply
  3. Tomi Engdahl says:

    Usb-laturissa piilee karmea yllätys: Sähkö­iskun vaara, vaikka olisi irti seinästä – ”Mitattiin 168 V jännite” https://www.is.fi/digitoday/art-2000009504873.html

    Reply
  4. Tomi Engdahl says:

    IKEA SMÅHAGEL USB charger teardown
    https://www.youtube.com/watch?v=G0yrCSD3FAM

    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.

    Reply
  5. Tomi Engdahl says:

    Poista nämä kaksi laturia heti käytöstä – viran­­omaiselta vakava varoitus

    Laturien käyttö altistaa sähköiskulle ja toisessa tapauksessa myös tulipalolle.

    https://www.is.fi/digitoday/art-2000009604219.html

    Reply
  6. Tomi Engdahl says:

    IKEA mini Smahagel teardown
    https://www.youtube.com/watch?v=lOJbxhA0E3E

    I opened this unit expecting it to be well built, and it didn’t disappoint. It even threw in a few surprises.

    This is IKEA’s smallest USB power supply intended for continuous use to power accessories like lights or ornaments. It only delivers 5V at 1A, so is less suited to high demand items like smartphones and tablets. But it will happily charge and power smaller items.

    I’ve always recommended the use of good quality branded USB power supplies for safety reasons. I regard IKEA power supplies as some of the most robust and safest units available. And they’re NOT expensive compared to the fashion brands.

    Reply
  7. Tomi Engdahl says:

    Wyness? Why not? WHY?
    https://www.kg4cyx.net/wyness-why-not-why/?fbclid=IwAR2eXejhPqBg4d3hYbOK_VHOmBidnKOWplKX3eAOA2Hg72B_v22UaPq0Dho

    I was cleaning up and found an old Six-Letter usb charger that I remembered having removed from service but I couldn’t remember why. I opened it up and got a clue right away.

    The unpopulated spots on the bottom are for the very important AC line noise filter to keep the high frequency switching pulses from the switch mode power supply from escaping into the house wiring and causing a myriad of interference to tv/radio reception and audio systems (among other things). In many cheap and nasty power supplies that have gone through quality fade, you will find this same issue. What should have been there is a common mode choke that looks like a small transformer, and a safety capacitor.

    Reply
  8. Tomi Engdahl says:

    Aside from apparently having both the ability to reproduce on their own and simultaneously never being around when you need one, USB chargers seem innocuous enough. The specs are simple: convert mains voltage to 5 volts, and don’t kill anyone while doing it. Both specs are typically met by most designs, but judging by ‘s latest USB charger teardown, the latter only just barely, and with a whole lot of luck….

    JUST HOW DODGY ARE CHEAP USB CHARGERS ANYWAY?
    https://hackaday.com/2023/11/03/just-how-dodgy-are-cheap-usb-chargers-anyway/?fbclid=IwAR2dtHu9mUJjrqO9ZLwBR12ogPwyFiBU5I58wmtBR1Cp-mKd5phKb6zi3mc

    Reply

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