Abstract: A passive power factor correction circuit includes: a DC capacitor and an input capacitor, coupled to a rectifying circuit and charged by a DC voltage from the rectifying circuit; an output capacitor, coupled to a load; first diode and a second diode, coupled to the input capacitor and the output capacitor; and an inductor, coupled to the load, the input capacitor and the output capacitor. Charging into and discharging from the DC capacitor are completed within a half cycle of an input AC voltage.

Abstract: The present disclose relates to a power active buck power factor correction device, comprising: a AC source; a rectifying device coupled to the AC source for receiving and rectifying the AC source so as to generate an input voltage; a first converting device coupled to the assistance device for receiving, transmitting, converting and storing energy; a load coupled to the first converting device; and an assistance device coupled to the first converting device for generating an assistance voltage. Specifically, the polarity of the assistance voltage is same with the input voltage, but is contrary to an output voltage, so that the first converting device may continue to work and receive an input current under the input voltage is smaller than the output voltage while the discontinue time of the input current is getting shorter so as to obtain the perfected power factor correction effect.

Abstract: The invention disclosed buck power factor correction system. The system includes: a first storing device, for storing and discharging energy; a first converter device, coupled to the first storing device, for transferring and converting energy; a second storing device, coupled to the first storing device, for storing and discharging energy; and a second converter device, coupled to the second storing device, for transferring and converting energy.

Abstract: A method for identifying a rated power of a HID lamp includes the steps of: outputting a first driving signal and a second driving signal to drive the HID lamp in order, and calculating a first electric characteristic variation of the HID lamp; and identifying the rated power of the HID lamp according to the first electric characteristic variation and a first default value.

Abstract: A light adjustment circuit for alternating-current light emitting diodes (AC-LED's) connected to an AC power supply and a plurality of AC-LED's comprises: a light adjustment unit, being capable of modulating AC power from the AC power supply while providing the plurality of AC-LED's with the modulated AC power; and a pulse width modulation (PWM) control circuit, being capable of modulating an external voltage signal in correspondence to variation in input AC power to enable each of the AC-LED's to achieve a predetermined brightness; wherein the AC-LED's are turned off by modulating the external voltage signal to prevent the AC-LED's from being burnt out when the input AC power is too high.

Abstract: A light adjustment circuit for alternating-current light emitting diodes (AC-LED's) connected to an AC power supply and a plurality of AC-LED's comprises: a light adjustment unit, being capable of modulating AC power from the AC power supply while providing the plurality of AC-LED's with the modulated AC power; and a pulse width modulation (PWM) control circuit, being capable of modulating an external voltage signal in correspondence to variation in input AC power to enable each of the AC-LED's to achieve a predetermined brightness; wherein the AC-LED's are turned off by modulating the external voltage signal to prevent the AC-LED's from being burnt out when the input AC power is too high.

Abstract: A control device for an electric fan comprising a power supply, a control means, a trigger pulse generator and a switch means, all connected in circuit with the motor of the electric fan, wherein the trigger pulse output of said trigger pulse generator is connected to trigger said switch means and is controlled through said control means to thereby achieve a stepless, variable speed control for the electric fan. Other forms of the device may further comprise a delay means, and/or delay reverse means, and/or wave generator means and/or any combination thereof, connected in the above circuit to accomplish stepless speed reduction and/or delay speed-down reverse and/or various kinds of imitative natural wind rotational speeds for the electric fan.