Semiconductor Device, and Display Device and Electronic Device Utilizing the Same

Abstract

A semiconductor device having a normal function means is provided, in which the amplitude of an output signal is prevented from being decreased even when a digital circuit using transistors having one conductivity is employed. By turning OFF a diode-connected transistor 101, the gate terminal of a first transistor 102 is brought into a floating state. At this time, the first transistor 102 is ON and its gate-source voltage is stored in a capacitor. Then, when a potential at the source terminal of the first transistor 102 is increased, a potential at the gate terminal of the first transistor 102 is increased as well by bootstrap effect. As a result, the amplitude of an output signal is prevented from being decreased.

1 . A semiconductor device comprising a first transistor, a second transistor, a third transistor, a first input terminal, and a second input terminal, said semiconductor device characterized in that:
 a source terminal of the first transistor is connected to a drain terminal of the second transistor,   a drain terminal of the third transistor is connected to a gate terminal of the first transistor,   the first input terminal is connected to a gate terminal of the third transistor and a gate terminal of the second transistor, and   the second input terminal is connected to the gate terminal of the first transistor through a rectifying element.