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  1. Estimating the cost required to resize a 60Hz transformer to comply with 50Hz

    It is a common concern to some technicians adapt equipment coming originally from countries whose frequency of electric public mains differs from its local, so that a modification becomes necessary, but depending on the size of equipment, the cost of the transformer may be the largest among the other inner devices, and a study can help determine the feasibility of conducting such a change. Obviously, such a study also determine if the power sizing is adequate to the load consumption.
  2. Sizing transformers for AC voltage stabilizers employing series topology

    This article is intended to be a quick guide on calculation of transformers used in AC voltage stabilizers which employes series topology. Such model is rarely used in low power equipments due to the relatively more complex control system required for drive the switching devices, but is specially suitable for employing at high power equipments, on what the weight of a conventional transformer (multi-taped) would be prohibitive, besides the fact that it reaches better resolution in the output compared ...
  3. Power Modules: alternative way for mounting

    Equipments such as Inverters and Rectifiers employ power modules as IGBTs, MOSFETs and TRIACs based on compact packages (modules). These components are mounted just above heat sink structure, and unlike PCB based packages, offer the possibility for assemble adopting an alternative approach.

    Basically consists of replacing each wiring connection for a metal plate (eg copper), and obviously, in order to achieve proper stacking, it is required to use a sheet of insulating material (eg ...
  4. C program for rotating bitmap characters ( 90 degree )

    When dealing with displays which haven´t character pattern at desired size, we need to insert character maps in the code program. Once draw entire table is a task somewhat painful, the next step is take a search on the Web for some available map file.

    However, after find it and put the map on the code, not rarely we realize that these characters were not drawn in the direction which the panel will be positioned, and we will need to make rotation for +/- 90 degrees, what means: ...
    Tags: bitmap, rotation Add / Edit Tags
  5. Scan code for parallel read on matrix keypad

    Requests for sample C code to deal with a matrix keypad is a recurrent question, what motivated me to share here some tips on an alternative implementation, not so widely employed.

    This code brings some benefits:
    • Allows reading combinations of multiple keys pressed at same row: 8(4 keys), 32(3keys), 48(2keys), 16(1key)
    • A little faster, due just 2 nibble scans are performed, instead 16 bit scan, performed on the classical approach.

    Find bellow its implementation, ...