How To select Power Adapter

Regulated DC Power Adapters

Choosing a regulated DC output voltage power adapter leaves less to consider, because the DC output voltage of a regulated (also known as stabilized ) power adapter always stays within the rated value regardless of the amount of current consumed by the load, as long as the rated output current of the power adapter is not exceeded. Why aren't all power adapters regulated ? The main reason is added cost. However, if cost is not an issue (and it's really not that bad), modern regulated switching power adapters offer some other distinct advantages over their unregulated counterparts.

Typical AC to DC regulated switching power adapter

While older regulated power adapters are really just like the previously described unregulated transformer type with a linear (analog) voltage regulator built in (and with many of the same limitations), today's modern "switch mode" regulated power adapters are a big step forward in technology. Gone, are the bulky, heavy, heat generating, internal voltage reduction transformers. Replaced by high speed digital switching circuitry that shrinks the overall size and weight, and greatly reduces heat generated "losses", while at the same time, greatly increasing the available output power. The result is much higher efficiency and tighter regulation control. In fact, many modern regulated switching power adapters offer multiple user selectable DC output voltages , (all regulated) and come with a range of user configurable output connectors. The user may select from a range of available output connector types and sizes, and change the output polarity of the connector as well. What's more, the permissible AC input voltage and frequency of modern switching power adapters have a range from 100 volts AC up to 240 volts AC and will operate equally well with 50 to 60 hertz (Hz) on their inputs. This makes them useful as a generic plug in "wall wart" power adapter virtually all over the world.

So now, with these modern switching power adapters, one small light weight power adapter may be all you need to charge or run your digital camera, camcorder, your cell phone, your electric shaver, cordless drill, power tools, gardening tools, car vac, flashlights, your portable printer, radio, media player, PDA, video game, portable TV, battery chargers, etc. If you tend to travel with just a few of these items, one modern switching power adapter can really lighten your load, and will likely save you money too.

How to select a regulated switching power adapter
With the many applications and advantages discussed above considered, selecting an regulated switching power adapter for your application can be summarized as follows:

check the power requirements and connector size specifications of the appliances or applications you wish to power.
select a regulated switching power adapter that will power as many of your applications as possible.

Conclusion

Choosing the correct power adapter isn't difficult when the power, performance requirements, limitations, and advantages are understood. Unregulated DC output power adapters are cheap and plentiful, and available in many voltage and current output variations, though they have more limitations than regulated switching power adapters do. Unregulated DC output power adapters are better suited for dedicated applications where portability and power sensitivity are not considered a big issue. Regulated switching power adapters are the much more versatile and efficient variety. If a user can power a small number of appliances with a single regulated switching power adapter, they can be more cost effective as well.