DC Adapter question

Funny you mention "real life" and then wander off into a fantasy land of speculation.

The fact of the "real life" matter is that none of your "sometimes" speculations apply to SMP wall worts.

That is what I meant by your mash of mumbo jumbo. One can 'speculate' anything but the real world case is that a regulated wall wort will have none of the characteristics you ponder as 'possible'.

Oh I understand them just fine and design them too. The difference is I don't try to obfuscate the practical matters with theoretical 'anything could be' speculations.

Wouldn't you be terrified it could be one of those unsuitable 'possibilities' of inferior regulation you just ranted about?

No need as it's appropriately silly as it stands.

Thanks. Knew it had to be unless someone had invented featherweight iron ;)

Oh, I wish that was the one that came with mine. Mine has the plug on the end, which means it sticks almost 3 inches out the wall, if you plugged it into a wall outlet.

That's the tolerance. They don't seem to mention load/line regulation %.

Look at the second 5 volt job 5 lines down: 2.5A 12.5W

Most of mine are plugged into power strips where such a compact arrangement is benificial. However, there are ways to deal all manner of wall warts.

Oops. I didn't notice the "U" suffix. Thanks.

I just happen to have a DLink DI-614+ here. DLink uses several sources of power supplies. This one is a: Fairway Electronics LTD Model: WN10A-050U Input: 100-240VAC 1.0A Max 50-60Hz Output: +5.0VDC 2.5A With such a wide input voltage range, it has to be a switcher.

I dunno about the 70% efficiency. Seems a bit low. Interesting that the sticker says 2.5A while the data sheet says 2.0A output. Oh-oh.

But wait! Couldn't the transformer be very light if it were ferrite and worked at a much higher frequency than 60 Hz? Oh, never mind.

Phil Weld>

Hehe. Sure. That's how a switcher does it.

Now HOW did you get a picture of my power strip?

Nope. I just checked with my wiz-bang new optical IR thermometer. My pile of 8 wall warts is running quite cool. I added two switcher wall warts to the top of the brown octopus connectors. Highest temperature was 83F (ambient is 71F). Most of the wall warts in the photo are not running. They go to my HP scanner, PCR-1000 receiver, Belkin KVM switch, Kyocera PDA phone, Radio Shock RC electric car charger, and other devices that are usually turned off. The ones running my BEFW11S4 and Efficient 5260 DSL modem are always on, but run quite cold. I suspect that if I turned everything on, it might get a bit warm. I could measure the dissipation and calculate the heat rise (based on black body radiation and surface area), but I'm lazy today.

I've had wall warts that ran very hot. Hot enough to burn my fingers when I touched them. The nice thing about the hot ones is that they don't last very long. I have a fair collection of replacements and connectors. A substantial number of my operating wall warts are replacement.

Incidentally, my photo of the octpus connectors plus power strip made the rounds on an electrical safety mailing list. The result was some really interesting email from electricians suggesting I was derranged, isane, dangerous, unsafe, and in violation of several NEC code sections. Absolutely nobody thought it was a good idea. Oh well.

The problem with the arrangement in the photo is that I have to glue the brown octopus connectors to the power strip, or it will tend to fall over. Xformers can only be installed in pairs. It works, but isn't the greatest. Currently, I'm using several of those overpriced flat two row power strips that are made to handle wall warts. The density is about the same but the plugs are much easier to deal with.

do you not find that the adaptors in the middle get kinda hot? I can practically cook toast on the power strip under my desk at work.

Here's an easy way to do it:

The current arrangement is different from the photo. I have three strips. One has the stuff that runs all the time and comes from the UPS. The other two get switched on/off depending on whether I'm at my messy desk, or gone. I don't switch them individually, but the grouping is better than leaving everything on all the time. Incidentally, the switcher type of wall wart turn off when there's no load.

It's been happening. Most of the current stuff comes with 12VDC wall warts. It's not in the name of standardization or anything so obvious. It's beause the 12VDC wall warts are cheaper than some of the other odd voltages. It also makes it easy to adapt for mobile and portable operation in the car.

Thanks for the URL. Have you ever seen a 3-prong AC adapter that attaches permanently (serrated contacts on the female end) to a USA 3-prong AC power plug and has a 'flip-up' ground pin. I've used it on 120 VAC power plugs for temporary lighting, but no longer know of a source. Any ideas? The URL you posted is quite useful, but does not seem to have that type of adapter.

Phil Weld>

Lucky you. My rather smaller (I only put one PSU per socket on the strip) runs rather warm. Maybe its the 240V we use over here :-)

That makes a difference I guess. How do you turn individual PSUs off? Most such units pump out heat even when the device they're supplying is off.

FWIW, It definitely isn't. One dodgy PSU heating up the strip could trip the rest over into overheat territory, and the whole lot could go up in flames. Still, its your funeral and Ive no doubt that everyone says "it never happens to me". Right up until it does... :-(

I reckon there's a market opportunity persuading manufacturers to standardise on voltage, so that we poor users could buy one buck fsckoff transformer and run say 7.5V and 12V DC rails under the desk.