Every electronic circuit will work as good as its power supply. However this is often overlooked. There are two main families of power supplies: the linear power supply and switch mode power supplies. Linear power supplies are easier to manufacture and to troubleshoot. But they have the disadvantage (especially for high power), the circuit is more complicated with the results of less power and heat faster than the switch mode power supply.
For a manufacturer, the choice of type of power supply will obviously influence the cost of manufacturing or integration. It should be noted that any hardware vendor does not make the most of its own power supply, and often will buy from a specialist. Creating a switching power supply by amateur is relatively difficult, even with the advent of integrated components provide most of the work.
In any case, strongly suggest a beginner in electronics to start with the realization of linearpower supply. Similarly, you are advised not to solve the problem of switch mode powersupply if you do not fully understand. However, in some articles that this will be discussed about the linear power supply.