Q: I bought the power adapter for the first-generation iPod nano and it works great, but I need to know if it is compatible with the fourth generation iPod nano.
A: As noted above, some older charging accessories are no longer compatible with the current iPod models, including the fourth-generation iPod. Whether or not your specific power adapter is compatible with the fourth-generation iPod will depend largely upon which one you purchased.
If you’ve purchased the official Apple power adapter for the first-generation iPod nano, then this will work fine. All Apple iPod power adapters manufactured since 2005 use 5V USB charging and will therefore work fine. In fact this applies to almost all of Apple’s recent accessories, with the iPod Hi-Fi speaker system being the only notable exception.
If you purchased a third-party power adapter, then this may be a more hit-and-miss proposition. Most third-party power adapters sold specifically for the iPod also use the 5V USB charging, but there are some that still use the older 12V FireWire charging method. However, if your charger is a two-piece model that uses an actual USB connector, then you can be fairly confident that this uses the 5V USB charging method. Some chargers, for example, simply provide a power plug adapter that connects to your existing iPod-to-USB cable. These chargers will likely work just fine with any current model of iPod.