A semiconductor device that functions as a relay station and is reduced in size is provided. The semiconductor device includes an operational amplifier, a first transistor and a first capacitor that are electrically connected to a first input side of the operational amplifier, and a first resistor and a second resistor that are electrically connected to a second input side. The second resistor is electrically connected to an output side of the operational amplifier, a gate of the first transistor is electrically connected to a first power supply, the first resistor is electrically connected to a second power supply, and at least a transistor included in the operational amplifier has a region overlapping with the first transistor.