Ebay switching power supply. 5.32v with no load. Safe?

Hey guys,
Bought a cheap switching power supply off of ebay, and it's putting out 5.32v with no load on it.

Food for thought: The spec for USB is +-5%, so USB ports could be putting out up to 5.25v

Is it safe to use directly on the 5v arduino pin? I think I remember up to 5.5v is safe, but i'm unsure.

The 5V atmega mcus are rated at 6V absolute maximum, and I'm not aware of any other components on an Arduino that are rated at a lower voltage. So 5.32V should be OK. You will probably find that the output voltage drops somewhat when you connect the Arduino to it.

dc42:
The 5V atmega mcus are rated at 6V absolute maximum, and I'm not aware of any other components on an Arduino that are rated at a lower voltage. So 5.32V should be OK. You will probably find that the output voltage drops somewhat when you connect the Arduino to it.

As I quick test, I connected a Nano and didn't see any voltage drop. But with an additional load on top of the Arduino I might.

Panici:
As I quick test, I connected a Nano and didn't see any voltage drop. But with an additional load on top of the Arduino I might.

It is totally dependent on the design quality of the regulator - only by testing will you know how well it regulates. Actually, you want it to change as little as possible.

For a "plug pack" (Wall Wart), you actually want it to be significantly greater than 5V so that the resistance of the cable (which is frequently ridiculously light gauge) is compensated to some extent. (It would actually help to have the regulator increase the voltage slightly as more current is drawn)

Having had a really bad experience at least once and being in an area where the mains supply may exceed 240V (presently 235 to my desk), I am always very anxious about switch-mode supplies operating with no load at all and therefore at a very short switching pulse width - I make a point of switching supplies on only after connecting, and off before disconnecting the load such as a laptop.

Which "power supply" is it? (my crystal ball is broken again)

Does it have an adjustment?

The voltage of a switching power supply shouldn't drop under normal loads.

You really need to put the PS under load before taking measurements. I often use a 4-cell flashlight bulb (6V) but these days one can go out to WalMart ( or equiv. ) and buy a 4-cell LED replacement for the bench:
4V6VLED-1T model at Walmart for $3.88. It is spec'ed at 6V, 0.13A and 0.8W, 40 lumens.
http://www.walmart.com/msharbor/ip/Rayovac-4V6VLED-1T-Rayovac-6V-LED-Replacement-Bulb-4-Cell/22086117

The LEDs have internal current limiting and with a current draw around 120+ MA they are ideal as test loads.

Ray