Abstract: A thin film transistor (TFT) that can prevent damage to a silicon layer under a gate electrode in an annealing process by using a first gate electrode having high thermal resistance and a second gate electrode having high reflectance and a method of manufacturing the TFT are provided. The method of manufacturing a TFT includes forming a double-layered gate electrode which includes a first gate electrode formed of a material having high thermal resistance and a second gate electrode formed of a metal having high optical reflectance on the first gate electrode, and forming a source and a drain by annealing doped regions on both sides of a silicon layer under the gate electrode by radiating a laser beam onto the entire upper surface of the silicon layer.

Abstract: A circuit for detecting the phase angle of a three-phase alternating current includes a plurality of low-pass filters installed at each input port for removing noise and high-frequency signals mixed in an alternating current input signal, a plurality of multipliers each for multiplying the signal output from each of the low-pass filter by a feedback signal, a subtracter for receiving the signals output from the plurality of multipliers and calculating an error between two signals, a loop filter for receiving the signal output from the subtracter and filtering the same, an integrator for receiving the signal output from the loop filter, time-integrating the same, and outputting an estimated digital phase angle signal, and a phase delay compensator installed between the subtracter and the loop filter, for compensating for phase delay of the input signal caused by the low-pass filters.