Regulated power supplies provide a cleaner power source and provide more protection to the devices it’s connected to. Regulated power supplies are not always the best or most economical way to go, some devices or products have their own regulators and protection circuits built-in, in this case a regulated power supply would not be necessary and the unregulated power supply would be the best choice. Always check with the manufacturer of a product or look at the adapter that your replacing and make the correct selection. Most specifications are listed on the adapter.
    Regulated power supplies will maintain a near constant voltage over the load range of the power supply and will provide a cleaner DC output with less AC ripple. Regulated power supplies also offer short circuit and current foldback protections. You can always use a regulated power supply in place of a non-regulated power supply as long as the voltage and current specifications match. Example: 12Vdc at 1 amp power supply will maintain a near constant voltage from a 100ma load to a 1 amp load. If more than 1 amp of current is exceeded the power supply will shutdown and go into current foldback.
    An un-regulated power supply will usually provide a higher output voltage than is listed and the current load against the power supply will cause this voltage to move up or down depending on the load. the DC output signal will contain much higher levels of AC ripple on the output. Never use a un-regulated power supply in place of a regulated power supply, damage to the device connected may result. Example: A 12Vdc power supply with no load would read about 14-15Vdc as you load the power supply down to near 1 amp the voltage would be around 10-12Vdc./ if you exceed the 1 amp the power supply would continue to operate but the voltage would continue to drop until the power supply gets to hot and fails.

Important AC adapter information

    Voltage: The voltage of the portable device and adapter must match. Some adapters have a DC output, and others have an AC output. Be sure you use the correct type of adapter, or damage will result.
    Current: Current of the adapter must be equal or more than the current required by the portable device 1000ma=1 amp.
    Plug Type: The plug on the adapter must fit the jack on the portable device for proper operation. There are many different sizes available, common sizes are 2.5mm, 3.5mm O.D. plugs and look like the connector in diagram A. 1.8mm, 2.1mm, 2.5mm O.D. coax plugs look like the connector in diagram B.
    Polarity: the positive and negative (+, -) must match the polarity of the portable device. Most DC input must have symbols nearby that look like the one pin diagrams C and D. Diagram C means that the outside of the jack is positive (+) and the inside is negative (-). Diagram D means the reverse.
    The adapter’s plug must match the portable device’s DC input jack or damage may result to the AC adapter or portable device. The positive terminal on the adapter’s plug must connect to the positive and the negative terminal on the adapter’s plug must connect to the negative.