| 摘要 |
PROBLEM TO BE SOLVED: To provide a radio alarm device reduced in size and stabilized in operation. SOLUTION: This radio alarm device is provided with: a reed switch RS for detecting an opened state of a window; a transmission circuit 2 for transmitting a wireless signal; and a control circuit 1 for controlling the transmission circuit 2 to transmit the wireless signal for notifying the opened state of the window. Electric power sources therefor are supplied from a battery BT comprising a button type primary battery and serving as the electric power sources for an abnormality detecting circuit and the transmission circuit, and from an electric double layer capacitor C having internal resistance lower than that of the battery BT and connected in parallel to the battery BT. The operation is stabilized because a drop of a voltage in the battery BT in a low temperature or the like is compensated by the electric double layer capacitor C, while reducing the size by using the button type battery BT. COPYRIGHT: (C)2008,JPO&INPIT
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