Abstract: A rotary cutting unit for a rotary saw has a cross bar and at least one cutting structure, wherein the cutting structure is in contact with the cross bar. The cross bar runs through sleeve holes. The center of gravity of the turning unit is located in an axis of the center of the sleeve holes. The axis is perpendicular to the transverse axis of the crossbar. The rotary saw selectively installs the rotary cutting unit of the corresponding specification, and it can quickly and easily change the aperture of the circular hole to be processed, and with high usability.

Abstract: A rotary cutting unit for a rotary saw has a cross bar and at least one cutting structure, wherein the cutting structure is in contact with the cross bar. The cross bar runs through sleeve holes. The center of gravity of the turning unit is located in an axis of the center of the sleeve holes. The axis is perpendicular to the transverse axis of the crossbar. The rotary saw selectively installs the rotary cutting unit of the corresponding specification, and it can quickly and easily change the aperture of the circular hole to be processed, and with high usability.

Abstract: A rotary cutting unit for a rotary saw has a cross bar and at least one cutting structure, wherein the cutting structure is in contact with the cross bar. The cross bar runs through sleeve holes. The center of gravity of the turning unit is located in an axis of the center of the sleeve holes. The axis is perpendicular to the transverse axis of the crossbar. The rotary saw selectively installs the rotary cutting unit of the corresponding specification, and it can quickly and easily change the aperture of the circular hole to be processed, and with high usability.

Abstract: A driving apparatus for driving a plurality of loads is provided. The driving apparatus includes a control unit, a driving unit, a current adjusting unit, and a detecting unit. The control unit outputs a control signal. The driving unit generates a driving signal according to the control unit to drive loads. The current adjusting unit is coupled to the loads to adjust the current passing through the same. The detecting unit is coupled to the current adjusting unit to detect a state of the current adjusting unit to generate a detecting signal. Here, the control unit adjusts the control signal according to the detecting signal.

Abstract: A hydraulic stun gun includes a housing holding two water tanks, two metal nozzles respectively connected to the water tanks through a respective water tube, two lead wires electrically connecting a battery set and a high voltage converter to the metal nozzles through a micro switch, a piston set for providing a compressed air pressure to the water tanks to force water out of the water tanks into the water tubes, two needle valves respectively mounted in the water tubes, a button operable to move open the needle valves and to switch on the micro switch for letting two jets of water be driven out of the metal nozzles and a high voltage low current be driven into the target through the two jets of water when the two jets of water touched the target.

Abstract: A controller for a driving circuit of power source comprises a frequency generator, a pulse width modulator, and a driving device. The frequency generator comprises a latch circuit. The frequency generator provides a pulse signal at a first frequency after the controller is started. After the frequency generator receives an indicating signal, the frequency generator changes the frequency of pulse signal from the first frequency to a second frequency and locks the frequency of pulse signal at the second frequency. The pulse width modulator provides a PWM signal according to the pulse signal and a feedback signal which indicates a status of electric power supply of the driving circuit. The driving device controls semiconductor switches according to the PWM signal.

Abstract: A driving apparatus and a method thereof are provided. The driving apparatus includes a control unit, a driving unit, a current adjusting unit, and a detecting unit. The control unit outputs a control signal. The driving unit generates a driving signal according to the control unit to drive loads. The current adjusting unit is coupled to the loads to adjust the current passing through the same. The detecting unit is coupled to the current adjusting unit to detect a state of the current adjusting unit to generate a detecting signal. Here, the control unit adjusts the control signal according to the detecting signal.

Abstract: A driving circuit for a light source is provided. The circuit is suitable for a light source with a plurality of light emitting diodes (LED). The circuit includes a first pulse width modulation (PWM) unit and a power conversion unit. The first PWM unit generates a first PWM signal. The power conversion unit generates a driving voltage signal for controlling the light source to perform forward bias operation or reversed bias operation according to the duty cycle of the first PWM signal.

Abstract: An apparatus for driving an LED includes a power conversion module and a protection module. The power conversion module shifts the potential of an input voltage upward or downward according to a duty cycle of a PWM signal, and outputs a driving signal to drive the LED. In addition, the protection module determines a state of a protection signal to control the operation of the power conversion module according to the potential of the driving signal. When the potential of the driving is greater than a first preset value and smaller than a second preset value, the power conversion module is controlled to stop outputting the driving signal. When the potential of the driving signal is not greater than the first preset value and not smaller than the second preset value, the power conversion module is controlled operating normally.

Abstract: A selection device for selecting an output state of a switch device is disclosed. The selection device includes a power source, a rectification element, a driving unit, and a control unit. The switch device includes an upper-arm switch and a lower-arm switch. The power source provides a power signal. The rectification element is coupled to the power source. The driving unit includes a totem circuit coupled to the upper-arm switch and a storage element coupled to the rectification element. The control unit transmits the power signal to the driving unit by the rectification element according to a control signal. The upper-arm switch is driven by the totem circuit to select the output state when the power signal is received by the driving unit.

Abstract: A driving apparatus used for driving a light source is provided. The driving apparatus includes a signal processing unit, a control unit, and a driving unit. The signal processing unit generates an enabling signal and a dimming signal according to an input signal. The control unit includes an enabling module and a dimming module. The enabling module enables the driving apparatus according to the enabling signal, and the dimming module generates a dimming driving signal according to the dimming signal. The driving unit adjusts the brightness of the light source according to the dimming driving signal.

Abstract: A DC/DC converter comprises a switch device, an inductor, a rectifying device and a capacitor. Switch device has a first terminal coupled to a DC power supply and a control terminal receiving a control signal. Inductor has a first terminal electrically coupled to a second terminal of switch device. Rectifying device has a first terminal electrically coupled to the first terminal of inductor. Capacitor has a first terminal electrically coupled to a second terminal of rectifying device, a second terminal electrically coupled to a second terminal of inductor. Switch device is switched between a first and second states based on control signals, the power of DC power supply is stored into inductor when switch device is in the first state; the power stored in inductor is released and provided to capacitor and LED module through rectifying device when switch device is in the second state.

Abstract: A driving circuit for a plurality of light-emitting diodes (LEDs) comprises a transformer, a driving module, and a protection module. The transformer has a primary coil and a secondary coil, wherein a first end of the primary coil is coupled to a voltage source. Furthermore, a second end of the primary coil of the transformer is coupled to the driving module. The driving module determines whether to deliver electrical power to the transformer according to a pulse-width modulation (PWM) signal and an error signal. The protection module is coupled to the secondary coil. When a driving voltage output by the transformer to the LEDs is less than a first preset voltage or greater than a second preset voltage, the protection module generates the error signal to the driving module.

Abstract: Disclosed is a power supply device driving lamp(s). An electrical isolation driver generates at least one switch signal according to at least one control signal. The control signal and the switch signal are electrically isolated from each other. A switch unit receives a voltage from a DC power source and switches the voltage to an oscillation signal. An electrical isolation transformer has a primary side and a secondary side. The primary side is coupled to the switch unit and receives the oscillation signal. The secondary side outputs an operating signal to drive the lamp. A controller generates the control signal according to a feedback signal indicating the electrical states of the lamp. The DC power source, the switch unit, and the primary side are coupled to a first ground. The secondary side and the controller are coupled to a second ground.

Abstract: A controller for a driving circuit of power source comprises a frequency generator, a pulse width modulator, and a driving device. The frequency generator comprises a latch circuit. The frequency generator provides a pulse signal at a first frequency after the controller is started. After the frequency generator receives an indicating signal, the frequency generator changes the frequency of pulse signal from the first frequency to a second frequency and locks the frequency of pulse signal at the second frequency. The pulse width modulator provides a PWM signal according to the pulse signal and a feedback signal which indicates a status of electric power supply of the driving circuit. The driving device controls semiconductor switches according to the PWM signal.

Abstract: A ceiling driller including a dust collector, a seat rod, a drill bit, an adjustment rod, two tool mounting seats, two machining tools, a spring, and a nut. The dust collector is provided with a plurality of dust collecting slots for collecting the machining dust which is forced into the dust collecting slots by the air current brought about by the rotational motion of the seat rod and the machining tools of the ceiling driller.