SONY AC-E454F power adapter

You can determine this yourself.  Put a very light load on one, say a 1K resistor.  Measure the voltage out.  If they are not putting out within 5% of the nameplate voltage, they're almost surely not regulated.

Walt, this adapter is almost certainly unregulated. it will read 4.5v with a 400 ma. load. To use them for Miller signs, I'd put 2 100 ohm 1/2 watt resistors across the signs power connections. this will draw about 100 ma from the supply, and should drop the voltage low enough that the sign won't burn out. Before plugging in the sign, measure the voltage across the resistors. if it's over 5 volts, try adding one more resistor. personally, i'd buy a 5vdc regulated supply-- they are real cheap on ebay-- and put 1 1A diode (1N4001) in/on the + output. this will reduce the 5V output to 4.3--4.5V, and you shouldn't have to worry about blowing the sign out.

hope this helps----

There are tons of regulated 5V adapters for cell phones and the like, I'd just get a regulated one, no extra components needed.  I must have at least three-four of the regulated 5V supplies in my wall wart box.

thanks for the clarifications.  I won't use these free ones - and I don't want to buy extra parts just so that I can use them.  I have a regulated one already that Chris has approved of that will power 10 signs.  I have 9 signs now so I was hoping that these free ones could help out.

thanks again - walt