The power adapter for my Polaroid Picture Frame failed. I thought it was a simple AC-DC
120 to 5 volt adapter, but reading the data says it's a Switching Mode Power Adapter,
120 vac to 5 vdc, 2.5 AMPS. That's a lot of amps. Can I  substitute ANY 5 vdc adapter that will handel 2.5 A or is there something different about a switching mode adapter?

I realize it's not a computer question but it's close and you are the only people I know to ask. Thanks. DixieflashNo. The power adapter you need is used for digital electronic devices that require well filtered and very steady constant voltage.
Few 'linear' power adapters do that. And not at 2.5 amps.

You can buy cheap switching adapters that will come close. But you have to be careful. Here is one the I know is a real switching power supply. It do supply 5 VOLTS for a D-link router, which sucks amps.

http://www.amazon.com/gp/product/B002FA5WE2/ref=olp_product_details?ie=UTF8&me=&seller=Thanks for your help. DixieflashBe sure to verify the polarity and voltage before you plug it i. Use a ten ohm resistor for a load. Or a 6 volt  light bulb. Voltage may not read OK with no load.Thanks, again, for that tip. Just what is the meaning of "Switching Mode" ?
Always trying to learn. DixieflashEarly PERSONAL computer designs use the PSU called a linear power supply. A hefty transformer would convert either to 120 or 240 AC power down to 5  and 12 colts. Actually, slightly higher voltages were produced when it was passed through a full-way rectifier and went into huge capacitors. But to get to the point, the power supply itself was not capable of supplying very stable power o the digital circuitry. So each circuit card in the computer had been at one or two linear regulators to produce the exact 5 V or 12 V  needed in the system. It was very wasteful and very bulky and read was an obstacle in the design of personal computers.
Apple Computer Co. broke the ice for the industry and they produced a small computer that had a switching power supply and the whole thing was very COMPACT and could easily fit on your desktop and not take up a lot of space. It was called the Apple II. Some sources say the Apple II was the first personal computer to use a switching power supply. That is why the computer was so compact and give off very little heat.
As to what the word 'switching' means , it basically means that the power supply does not run at the 50 or 60 Hz line frequency. Instead a switching circuit breaks it up with her pulses at a much higher rate something like 25,000 Hz. At the higher FREQUENCIES transformer cores can be made much smaller and much more efficient. A 75 watt high-frequency core can fit in the palm of your hand. For more information about how switching power supplies work, let me refer you to an article that is helpful.
http://en.wikipedia.org/wiki/Switched-mode_power_supply
Small linear power supplies are still used for applications that allow for POOR regulation and limited current. These typically are called wall warts, a reference to those of transformers that plug into a wall socket. They are suitable for such things as toys and boom boxes other gadgets that do not require high quality low voltage.
Wow - I really learned something there. Thanks, again, for playing teacher. DF