Abstract: An under voltage protection device includes a voltage detector and a starting unit. The voltage detector includes a diode, a variable resistor, a transistor and a fixed-resistance resistor. The starting unit includes a second transistor. When a voltage of the external voltage source is smaller than a voltage of the diode, a voltage between an emitter node and an collector node of the first transistor is smaller than a threshold voltage present between a gate node of and a source node of the second transistor such that the starting unit is turned off. When the voltage of the external voltage source is larger than the voltage of the diode, the voltage between the emitter node and the collector node is larger than the threshold voltage present between the gate node and the source node such that the starting unit is turned on.

Abstract: A miniaturized voltage-transforming device includes a first circuit board and a second circuit board parallel to and separated from each other by a predetermined distance so that there is no physical connection therebetween, and a transformer having a plurality of primary-side pins and a plurality of secondary-side pins, wherein the transformer is located beside the first circuit board and the second circuit board, and has its primary-side pins and secondary-side pins directly or indirectly connected to the first circuit board and the second circuit board physically, so that the transformer is electrically connected to the first circuit board and the second circuit board via the primary-side pins and the secondary-side pins.

Abstract: An ultralow no-load conduction loss DC converter includes a DC power source, a transformer having a first winding, a first MOSET and a PWM controller at the primary side and a second winding, a third winding, a drive control unit, a rectifier unit and a second MOSFET at the secondary side. The second MOSFET, the drive control unit and the rectifier unit constitutes a combination circuit electrically coupled between one end of the second winding and one end of the third winding. The second MOSFET has set therein a body diode. The second winding and the second MOSFET forms a combination circuit electrically connected to a load. Thus, the decision to turn off the drive control unit is made at the secondary side so that non-load conduction loss can be minimized.

Abstract: A receptacle includes an electrically insulative bottom wall, and an electrically insulative upright wall upwardly extended from the border of the bottom wall, the upright wall having a back wall portion corresponding to the rear side of the bottom wall. The bottom wall is adapted for mounting at a circuit board or electronic device to hold a transformer in such a manner that the lead wires of the primary winding of the transformer are disposed at the front side of the bottom wall; the insulated lead wires of the secondary winding of the transformer are extended over the top edge of the back wall portion and then turned downwardly and bonded to the circuit board or electronic device.

Abstract: A metal shell and plate member welding method includes the steps of: A) preparing a shell and a plate member, B) applying a solder material to the plate member, C) attaching the shell to the solder material at the plate member to form a semi-finished product and then putting the semi-finished product in a fence of a bottom tool member, D) moving the bottom tool member to insert the semi-finished product and the fence into the space surrounded by an induction coil of an induction heater and then pressing a top tool member on the semi-finished product, E) operating the induction coil to heat the border edge of the shell to a temperature level about 20° C.˜100° C. over the melting point of the solder material, thereby melting the solder material, and F) cooling down the solder material to finish the welding procedure.

Abstract: An electronic apparatus and an insulation structure thereof are provided. The electronic apparatus comprises a circuit board, an insulation structure and a transformer. The circuit board has a top surface, a bottom surface and an opening extending across the top surface and the bottom surface. The insulation structure has a first standing plate and a top plate. The first standing plate is connected with the top plate, and the first standing plate is disposed on the circuit board and inserted into the opening of the circuit board. A bottom surface of the top plate faces towards the top surface of the circuit board. The transformer is disposed on the top plate of the insulation structure and on the top surface of the top plate.

Abstract: A fastener for fastening a heat sink and a heat-generating element includes a bended flexible main body, an upper hook portion, and a lower hook portion. The heat sink includes a plurality of fins. The upper hook portion extends from an upper end of the main body for matching the fins and hooking the heat sink. The lower hook portion extends from a lower end of the main body for hooking the heat-generating element.

Abstract: A heating coil includes at least one winding having a plurality of approach portions. Each of the approach portions is close to a workpiece surrounded by the winding. The winding defines two electrodes at two ends thereof for electric connection with a high-frequency power source. Accordingly, the workpiece can be heated more equably than that of the prior art.

Abstract: A surface mount contact includes a conducting pin having a shank, a first end at one end of the shank and second end at the other end of the shank, a first annular flange extending around the periphery of the shank and spaced between the first end and the second end and a second annular flange extending around the periphery of the shank and spaced between the second end and the first annular flange, and a thermoplastic connection member joined to the second end of the conducting pin and spaced from the second annular flange at a predetermined distance so that there is a room for the user to judge the connection status and quality between the conducting pin and the thermoplastic connection member during surface mounting, assuring bonding stability.

Abstract: A power converter includes at least one electric control switch, an electric current detecting and converting unit, a power controller, and a voltage detecting and controlling unit at the primary side; and a synchronous rectifying circuit, two MOSFETs, and an oscillating loop. During the actual operation, electric current detecting and converting unit outputs an AC voltage signal to the power controller and outputs a DC voltage signal to the voltage detecting and controlling unit, and then voltage detecting and controlling unit compares with a reference voltage to turn off the synchronous rectifying circuit at the no-load mode and to rectify via a body diodes of the MOSFETs. Accordingly, the power converter can reduce the power wastage at the no-load mode to be energy-saving.

Abstract: A power converter includes at least one electric control switch, an electric current detecting and converting unit, a power controller, and a voltage detecting and controlling unit at the primary side; and a synchronous rectifying circuit, two MOSFETs, and an oscillating loop. During the actual operation, electric current detecting and converting unit outputs an AC voltage signal to the power controller and outputs a DC voltage signal to the voltage detecting and controlling unit, and then voltage detecting and controlling unit compares with a reference voltage to turn off the synchronous rectifying circuit at the no-load mode and to rectify via a body diodes of the MOSFETs. Accordingly, the power converter can reduce the power wastage at the no-load mode to be energy-saving.

Abstract: A synchronous rectifier drive circuit includes a primary side and a secondary side. The primary side has a first coil winding, a first MOSFET, an auxiliary MOSFET, an auxiliary capacitor, and an input power source. The secondary side has a second coil winding, a DC voltage source, a second MOSFET, a third MOSFET, a fourth MOSFET, a fifth MOSFET, and an inductor. The gate of the second MOSFET is connected with the source of the fourth MOSFET. The gate of the third MOSFET is connected with the source of the fifth MOSFET. The inductor has two ends, one of which is connected with the drain of the third MOSFET. Accordingly, the synchronous rectifier drive circuit can lessen the variation of pulse wave of the drive voltage and refrain the surge voltage to protect the electronic elements.

Abstract: A flyback converter is comprised of a primary side and a secondary side. The primary side includes a primary winding and a switch both connected in series. The secondary side includes a secondary winding, a tertiary winding, a first resistor, a capacitor, a second resistor, and an MOSFET (metal-oxide-semiconductor field-effect transistor). The first resistor, the capacitor, and the second resistor are connected in series and together connected in parallel with the tertiary winding. The MOSFET is connected in parallel with the first resistor at its gate and source. Accordingly, when the switch is turned on/off, the power energy provided at the primary side can be transferred to the secondary side in a flyback manner.

Abstract: A flyback converter is comprised of a primary side and a secondary side. The primary side includes a primary winding and a switch both connected in series. The secondary side includes a secondary winding, a tertiary winding, a first resistor, a capacitor, a second resistor, and an MOSFET (metal-oxide-semiconductor field-effect transistor). The first resistor, the capacitor, and the second resistor are connected in series and together connected in parallel with the tertiary winding. The MOSFET is connected in parallel with the first resistor at its gate and source. Accordingly, when the switch is turned on/off, the power energy provided at the primary side can be transferred to the secondary side in a flyback manner.

Abstract: A heat-dissipative coating is composed of a plurality of granules having a predetermined thickness and disposed on an object, and is insulated and highly thermal-conductive. The total surface area of the granules is greater than that of the heat-dissipative coating disposed on the object, thereby rendering preferably effective heat-dissipation.

Abstract: A heat-dissipative coating is composed of a plurality of granules having a predetermined thickness and disposed on an object, and is insulated and highly thermal-conductive. The total surface area of the granules is greater than that of the heat-dissipative coating disposed on the object, thereby rendering preferably effective heat-dissipation.

Abstract: A heat-dissipating circuit board assembly is composed of a heat-conducting base board and a circuit board. The heat-conducting base board includes an insulating heat-conducting layer disposed thereon and a plurality of bonding pads disposed on the insulating heat-conducting layer and never connected with one another. The circuit board that is single-layered or multiple-layered includes a plurality of electronic components at at least one side thereof and a plurality of heat-dissipating zones at a side thereof. The heat-dissipating zones are connected with heat-generating elements of the electronic components and in a corresponding position to the bonding pads. The heat-conducting base board is connected with the heat-conducting base board by the melted bonding pads that are melted by heating and further disposed therebetween.

Abstract: A packaging process of a circuit board involves a first step in which the circuit board is provided with a predetermined number of pins and is then arranged in the lower mold of a first molding tool. The upper mold of the first molding tool is joined with the lower mold before the resin is injected. The mold is then opened to remove therefrom a semifinished product, which is provided with a metal passivation layer and is subsequently placed in a second molding tool to carry out a second packaging operation. The second molding tool is opened to remove therefrom a finished product.

Abstract: A circuit board packaging process comprises the steps of: (a) connecting a circuit board with a plurality of pins by soldering; (b) attaching a metal housing to the cavity of the lower mold of a molding tool, the lower mold cavity has a resin feeding port; the metal housing has a through hole corresponding in location to the resin feeding port; (c) attaching a metal piece to the upper mold of the molding tool; the metal piece has a plurality of through holes for receiving therethrough the pins; the upper mold cavity has a plurality of insertion holes corresponding in location to the through holes; the circuit board is retained under the metal piece such that the pins are inserted into the insertion holes via the through holes; (d) closing the upper and the lower molds to enable the circuit board to be located between the metal piece and the metal housing; (e) injecting resin toward the through hole from the resin feeding port; (f) upon completion of the cooling of the molding tool, removing a finished product