Abstract: A pixel circuit in an organic light emitting device capable of realizing high gradation representation by self-compensating a threshold voltage, and a method for driving the same. The pixel circuit includes an electroluminescent element for emitting light in response to an applied driving current. A first transistor delivers a data signal voltage in response to a current scan line signal. A second transistor generates a driving current to drive the electroluminescent element in response to the data signal voltage. A third transistor connects the second transistor in the form of a diode in response to a current scan signal to self-compensate the threshold voltage of the second transistor. A capacitor stores the data signal voltage delivered to the second transistor. A fourth transistor delivers a power supply voltage to the second transistor in response to a current light-emitting signal.

Abstract: Alphabet input apparatus and method are provided. In the alphabet input apparatus, one alphabet is determined by pressing two keys of a keypad to which ten basic figures made by analyzing shapes of alphabets are allocated respectively. Further, each alphabet corresponds to a combination of two keys depending on the order of handwriting the alphabet. Thus, the user can conveniently input alphabets with the same manner as a Korean handwriting manner without memorizing the key arrangement. Since the user can input all alphabets using limited keys, the alphabet input apparatus may be used as a small-sized keyboard or keypad in small-sized and multi-function electronic equipments such as a mobile phone.