US Patent 7629612 Semiconductor device

Solved is a problem of attenuation of output amplitude due to a threshold value of a TFT when manufacturing a circuit with TFTs of a single polarity. In a capacitor (105), a charge equivalent to a threshold value of a TFT (104) is stored. When a signal is inputted thereto, the threshold value stored in the capacitor (105) is added to a potential of the input signal. The thus obtained potential is applied to a gate electrode of a TFT (101). Therefore, it is possible to obtain the output having a normal amplitude from an output terminal (Out) without causing the amplitude attenuation in the TFT (101).