Semiconductor device and driving method thereof

A semiconductor device comprising:

• a display element;
• a transistor electrically connected to the display element;
• a first switch electrically connected to the transistor;
• a second switch electrically connected to the transistor;
• a first current source electrically connected to the first switch;
• and
• a second current source electrically connected to the second switch;
• wherein the first current source feeds a first current between the source and the drain of the transistor through the first switch so that the gate terminal of the transistor has a first potential, and
• wherein the second current source feeds a second current between the source and the drain of the transistor through the second switch so that the gate terminal of the transistor has a second potential.

A semiconductor device comprising:

• a load;
• a transistor electrically connected to the load;
• a first switch electrically connected to the transistor;
• a second switch electrically connected to the transistor;
• a first current source electrically connected to the first switch;
• a second current source electrically connected to the second switch;
• wherein the first current source feeds a first current between the source and the drain of the transistor through the first switch so that the gate terminal of the transistor has a first potential,
• wherein the second current source feeds a second current between the source and the drain of the transistor through the second switch so that the gate terminal of the transistor has a second potential, and
• wherein a third current flows to the load when the first switch and the second switch are turned off.

A semiconductor device comprising:

• a load connected in series to a first switch;
• a constant current source connected in series to a second switch;
• a first power source line electrically connected to the load;
• a first transistor electrically connected to the load and the constant current source;
• a second transistor electrically connected to the first transistor;
• a second power source line electrically connected to the second transistor;
• and
• a third power source line electrically connected to gate electrodes of the first and the second transistors,
• wherein the gate electrode of the first transistor is electrically connected to a drain electrode of the first transistor through a third switch;
• and
• wherein a source electrode of the second transistor is electrically connected to a drain electrode of the second transistor through a fourth switch.

A semiconductor device comprising:

• a load;
• a transistor electrically connected to the load through a first switch;
• a first current source;
• a second current source;
• and
• a capacitor electrically connected to a gate terminal of the transistor,
• wherein any one of a source terminal and a drain terminal of the transistor is connected to the first current source and the second current source through a second switch,
• wherein the second current source feeds a first current to the transistor so that the gate terminal of the transistor has a first potential, and
• wherein the first current source feeds a second current to the transistor so that the gate terminal of the transistor has a second potential.