Valueline USB AC charger VLMP11955B
Official specifications:
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Input Power: AC 100-240V 50/60Hz
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Output Power: DC 5V-2.1A
I got it in a plastic bag.
Measurements
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Power consumption when idle is 0.1 watt
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Usb output is coded as Apple 2.1A
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Weight: 49.6g
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Size: 71.5 x 39.0 x 39.0mm
This small adapter can deliver the rated current and a bit more (the overload protection looks fine).
It works about the same on 120VAC
No problems running one hour at 1A.
The temperature photos below are taken between 30 minutes and 60 minutes into the one hour test.
M1: 64,6°C, HS1: 78,8°C
HS1 is the transformer.
M1: 54,9°C, M2: 55,6°C, HS1: 60,6°C
M1: 57,4°C, HS1: 64,8°C
HS1 is the transformer.
M1: 61,3°C, HS1: 67,5°C
At 0.5A the noise is 36mV rms and 384mVpp.
At 1A the noise is 40mV rms and 317mVpp.
At 2A the noise is 56mV rms and 410mVpp.
Tear down
My vice and a mallet could open it.
The plastic shield inside the box is used for isolation between mains and low volt side.
At the mains input there is a fuse and a blue safety capacitor. Between the two capacitors is an inductor with shrink wrap around. The mains switcher transistor (Q1) is next to the transformer. The transformer has wires to the low volt side, where the rectifier diode is placed.
The fuse (F1) is next to the mains input wire.
Here the inductor between the two mains capacitors can be seen. One of the capacitors has shrink wrap on top of the plastic isolation.
From this side the rectifier diode and the transformer can be seen.
One of the capacitors is mounted on top of the usb connector and has heat shrink on its legs.
This side contains a bridge rectifier (DB1) and the mains switcher controller. There is four resistor for coding the usb output (R15..R18).
Safety distance looks good.
Testing with 2830 volt and 4242 volt between mains and low volt side, did not show any safety problems.
Conclusion
Generally this small charger looks well designed and with good performance, the noise is slightly high.
Notes
Charger was supplied by Pro backup (probackup.nl)
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