| 摘要 |
PURPOSE: To evade adverse effect caused by the rise of the internal resistance of a battery by obtaining the internal resistance of the battery and informing a user of a battery exchange period when the obtained internal resistance exceeds a reference value. CONSTITUTION: A frame processing circuit 7 samples a battery voltage VBATT outputted from the battery 12 at a prescribed timing, analog/digital converts a sampling value and the obtained battery voltage data is stored in a memory inside. The battery voltage data D1 are read by a control part 4. The control part 4 checks a battery state based on the battery voltage data D1, and when the residual amount of the battery 12 is not present as the result, rings alarm sound from a speaker 10 and displays that the residual amount of the battery 12 is not present at a liquid crystal display device 11. Also, the control part 4 displays that it is the exchange period of the battery 12 at the liquid crystal display device 11 when it is detected that the internal resistance of the battery 12 is larger than the prescribed reference value. |
