A signal transmitter system for an animal training system including an electrical impedance loop, a signal generator and a power supply. The semiconductor device includes a first oxide semiconductor film, a gate electrode overlapping with the first oxide semiconductor film, a first gate insulating film between the first oxide semiconductor film and the gate electrode, and a second gate insulating film between the first gate insulating film and the gate electrode. The inlets are wider and therefore refill flow rates are higher. The organic acid is preferably a polyhydric carboxylic acid. Thus, display control of a displayed image is carried out without providing additional operating keys.