| 摘要 |
PROBLEM TO BE SOLVED: To provide a buzzer device the fault of which is appropriately detected without imposing a burden on an owner.SOLUTION: A portable communication device includes a casing, an alarm, and a control part. The alarm includes: a fuse whose one end is connected to first power supply potential; a buzzer whose one end is connected to the other end of the fuse; a transistor in which one of a source or a drain is connected to the other end of the buzzer and the other of the source and the drain is connected to second power supply potential, and a resistor connected between the connection part of the buzzer and the transistor and the second power supply potential. The control part turns a drive signal applied to the gate of the transistor on or off, and determines the fault of the alarm on the basis of a monitoring signal which is the potential of the connection point of the buzzer and the transistor. |
