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. A fifth
transistor provides the driving current, provided from the second
transistor, for the electroluminescent element in response to the current
light-emitting signal.