Abstract: Disclosed are electronic control gears for LED light engines able to improve power factor by way of gearing up or down the LED current and the AC input current in response to and in synchronization with the AC input voltage. Moreover, the disclosed electronic control gears could further reduce flicker phenomenon and total harmonic distortion when used in collocation with disclosed valley fillers, filling the LED current valleys only during the dead time, and in conjunction with disclosed dummy loads, ramping up or down the AC input current only during the dead time.

Abstract: An economical device for lighting lamps such as discharge tubes. The lamp-lighting apparatus has an inverter transformer, a switching circuit connected with the primary winding of the inverter transformer and acting to perform switching for converting a voltage from an input power supply, a shunt transformer connected in series with the secondary winding of the inverter transformer, lamps connected in series with the shunt transformers, and a control circuit for producing a control signal to control the switching performed by the switching circuit based on the voltages at the junctions of the shunt transformer and each of the lamps without directly detecting the voltage applied to the secondary winding of the inverter transformer. The number of protective circuits can be reduced. Consequently, the cost can be reduced.

Abstract: The present invention discloses a field emission display including: a monitoring emitter applied to a constant voltage wherein the monitoring emitter is installed at an outer portion of an active area of a cathode plate; and a current measuring electrode applied to a constant voltage to measure the current flowing to the monitoring emitter wherein the current measuring electrode is disposed at an outer portion of an active area of an anode plate. In addition, a method for measuring a vacuum degree of a field emission display, includes the steps of: measuring current variations of a monitoring emitter by electron emission of a display emitter, when the vacuum degree is changed by gas molecules outgassed from a panel of the FED; and monitoring variations of the vacuum degree in the panel of the FED according to the variations of the measured anode current.