Abstract: A portable electronic device includes a housing, a drop detection part located on the housing that detects when the device is dropped into water, a light emission part located within the housing, and a light-emission control circuit located within the housing that controls emission of light from the light emission part when the drop detection part detects that the device is dropped into the water. The device is configured to have a buoyancy, and the buoyancy and a center of gravity of the device are configured to let the device float stably in a left-right lateral direction.

Abstract: A portable electronic device includes a housing, a drop detection part located on the housing that detects when the device is dropped into water, a light emission part located within the housing, and a light-emission control circuit located within the housing that controls emission of light from the light emission part when the drop detection part detects that the device is dropped into the water. The device is configured to have a buoyancy, and the buoyancy and a center of gravity of the device are configured to let the device float stably in a left-right lateral direction.

Abstract: A drop detection part that detects drop into the water, a light emission part, and a light-emission control circuit that makes the light emission part emit light when the drop detection part detects the drop into the water. Also, the light emission part may be disposed on the side to be turned up by buoyancy when the device is dropped into the water and the drop detection part may be disposed on the side to be turned down in the case of the drop into the water, for example.

Abstract: A wireless communication device includes a speaker grille, a built-in speaker provided behind the speaker grille, and an output amplifier connected to the built-in speaker. A voltage applied to the output amplifier is increased to a level higher than the level of voltage applied to the output amplifier while audio signals are being produced, and instead of the audio signals, low-frequency continuous signals are applied to the output amplifier. By increasing the voltage applied to the output amplifier to a level higher than the level of voltage applied to the output amplifier while audio signals are being produced, the amplitude of the voltage applied to the speaker is increased. Also, instead of the audio signals, low-frequency continuous signals are applied to the output amplifier so that the speaker produces a higher sound pressure than while audio signals are being produced to discharge water in the speaker grille under the sound pressure.

Abstract: A drop detection part that detects drop into the water, a light emission part, and a light-emission control circuit that makes the light emission part emit light when the drop detection part detects the drop into the water. Also, the light emission part may be disposed on the side to be turned up by buoyancy when the device is dropped into the water and the drop detection part may be disposed on the side to be turned down in the case of the drop into the water, for example.

Abstract: A wireless communication device includes a speaker grille, a built-in speaker provided behind the speaker grille, and an output amplifier connected to the built-in speaker. A voltage applied to the output amplifier is increased to a level higher than the level of voltage applied to the output amplifier while audio signals are being produced, and instead of the audio signals, low-frequency continuous signals are applied to the output amplifier. By increasing the voltage applied to the output amplifier to a level higher than the level of voltage applied to the output amplifier while audio signals are being produced, the amplitude of the voltage applied to the speaker is increased. Also, instead of the audio signals, low-frequency continuous signals are applied to the output amplifier so that the speaker produces a higher sound pressure than while audio signals are being produced to discharge water in the speaker grille under the sound pressure.

Abstract: Active carbon having a pore size distribution obtained from a nitrogen adsorption isothermal line such that the volume of pores having a pore diameter of less than 15 .ANG. is at least 0.25 ml/g and constitutes at least 40% of the total volume of pores having a pore diameter of at most 300 .ANG., and the volume of pores having a pore diameter of from 100 to 300 .ANG. constitutes at least 10% of the total volume of pores having a pore diameter of at most 300 .ANG..