Abstract: A power supply with optional types of plugs, composed by one universal body and replaceable plug, is disclosed. The universal body includes a plurality of blocks, a circular recess, an elastic switch key, and two conductive plates; whereas the plugs could be different specifications of plug with opposite blocks and two conductive plates, the block holes and blocks include a set of error-proof block hole and error-proof block which posses a block slot to hold the fan-shaped block.

Abstract: Disclosed is a transformer bobbin with hipot-protect structure. The bobbin is integrally formed from plastic material through injection molding and includes a central shaft portion and an outer frame portion at two ends of the central shaft portion. When the bobbin is formed during molding, the outer frame portion is extended from one or two lateral outer ends thereof for a length and therefore forms one or two extended portions on the bobbin. Upright rib or ribs may be additionally provided on top surface of the extended portion. The extended portion provide increased creepage distance between pins connected to outer end surfaces of the bobbin and the core of the transformer to effectively prevent hipot from transiting from pins at one end to pins at the other end by crossing over the core directly.

Abstract: A hipot barrier structure for a transformer for preventing instantaneous hipot from transiting from pins at high-tension side to pins at low-tension side directly via a conductive core of the transformer, so that damages to the whole circuitry can be avoided to comply with required safety code. The barrier structure includes a barrier member made of insulating material and having a generally C-shaped cross-section for fitly covering the high-tension side of the core in a tight fit relation and forming an outer layer of the core at the high-tension side. The barrier member increases a creepage distance between the pins and the conductive core and therefore effectively prevents a hipot from directly crossing over the core.

Abstract: A coil rack for transformer including a coil winding seat around which an inner and an outer coil windings are sequentially provided. Axially extended through holes are formed on a bottom of the coil winding seat at positions spaced below the inner coil winding. Stoppers are provided to separately locate radially outside the through holes. Each of the stoppers is provided at a bottom surface with a radially extended open channel of which one end leads to the through hole and another end to an outer end of the coil rack. Free ends of the inner coil winding are separately guided downward via the axially extended through holes and then outward via the radially extended open channels on bottom surface of the stoppers to avoid contact with the outer coil winding and any possible short circuit.

Abstract: A miniature transformer is provided at each end surface of a bobbin thereof with two spaced principal pins and two spaced dummy pins located between the two spaced principal pins. The dummy pin each is an integral extension from a rear end of an extended rear section of one adjacent principal pin embedded in the bobbin. The extended rear section extends obliquely forward toward a central area of the end surface of the bobbin and then turns straight forward to project from the end surface to form the dummy pin. The dummy pin each is provided at an inner side with a curved notch for a lead from windings on the miniature transformer to wind around there without further reducing a small distance between two adjacent dummy pins. Since the dummy pins are located between and shorter than the principal pins, they are protected by the principal pins without being easily touched or pulled to cause broken leads that would result in high bad yield in the production of the miniature transformer.