UK Charger 5V 2A JHD-AP012B-05200AB

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Official specifications: I got it from Ebay

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Measurements

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The charger can deliver about 2.9A before overload protection kicks in.

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This drops to about 2.8A at 120VAC

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The charger can deliver 2A for one hour.
The temperature photos below are taken between 30 minutes and 60 minutes into the one hour test.

Temp7117

M1: 50.3C, HS1: 56.0C

Temp7118

M1: 63.9C, HS1: 69.9C
HS1 is the rectifier diode.

Temp7119

HS1: 61.1C
Again HS1 is the rectifier diode.

Temp7120

M1: 52.3C, HS1: 56.5C

Temp7121

HS1: 74.8C
HS1 is the transformer.

10ohm

At 0.5A the noise is 5mV rms and 106mVpp.

5ohm

At 1A the noise is 7mV rms and 145mVpp.

2ohm

At 2.5A the noise is 7mV rms and 97mVpp, this is very low noise.




Tear down

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It was a bit hard to break apart, but some screwdrivers uses as prybars worked.

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A very compact design, it must be expensive to mount all the parts.
At the mains input is a fuse in shrink wrap and a MOV to handle mains transients. The bridge rectifier is four diodes (D1..D4). There is two smoothing capacitors (C1 & C2) with a inductor between. The mains switcher transistor (Q1) is next to the safety capacitor (CY1).
On the low volt side is a large rectifier diode (D7) and two smoothing capacitors (C5 & C?) with a inductor between.
There is a opto feedback.

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The bottom of the circuit board do also have a lot of parts, mostly passive, but there is the switcher IC (U1) and on the low volt side the reference (U3: 431). There is space for a auto coding chip (U4), but it is not mounted.

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Across a slot there must be 4 mm between mains a low volt side, there is a lot more space here. Directly across circuit board there must be above 6mm, but here it is slightly below 6mm!


Testing with 2830 volt and 4242 volt between mains and low volt side, did not show any safety problems.



Conclusion

The charger is a bit old fashioned in the design, but it works nicely with enough current and low noise. Safety is not perfect, but the problem is minimal.



Notes

The USB charger was supplied by a reader for review.

Index of all tested USB power supplies/chargers
Read more about how I test USB power supplies/charger
How does a usb charger work?