In any electronics products the power section is one of the vital part and it plays a major role in quality functioning of a board. For most of the electronics product the power source is the AC supply which we have in our house power sockets. So it is necessary to convert this AC power into DC voltage levels which is applicable for the components in the board. Hence it is important to understand about power conversion and the quality it shall have.
Power conversion blocks:
The high AC voltage (230V/110V) is given to a step down transformer and it is reduced to lower level depending upon the desired DC output level. The step down transformer shall have appropriate turns ratio - to convert 240VAC into 12VAC, turns ratio of 240/12 = 20:1 shall be used. But if the desired DC level is 12V then the reduced AC voltage shall be chosen as 15V, this slightly higher level is required to compensate losses which will occur in subsequent steps.
The stepped down AC voltage is given to rectifier to convert AC into DC voltage. The diode based rectifiers are normally used, the popular one is wheatstone bridge full wave rectifier. The resultant DC voltage is unsmoothed one which means the output level is not a constant one and it will vary within a certain limits.
The unsmoothed output is converted into smoothed DC voltage by filtering stage. The resultant output DC voltage is similar to straight line with certain level and with very low variation.
The resultant filtered DC voltage is used to power the electronic boards with the use of regulators or DC DC converter based on the requirements.
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