Abstract: According to an aspect, an electronic device includes: a piezoelectric element; a first sound generating unit that is vibrated by the piezoelectric element and generates a vibration sound transmitted by vibrating a part of a human body; and a second sound generating unit that generates an air conduction sound.

Abstract: A mobile electronic device includes: a communication unit configured to perform short-distance communication with a first device, a notification unit configured to perform a local notification for a user of the mobile electronic device, and a controller configured to cause the notification unit to perform the local notification to the user when the short-distance communication with the first device is incapable of being performed. When the short-distance communication between the mobile electronic device and the first device is incapable of being performed, the controller is configured to transmit, to a second device, an inquiry as to whether the short-distance communication between the first device and the second device is capable of being performed.

Abstract: According to one of some aspects, a mobile electronic device includes: a communication unit configured to perform short-distance communication with a first device; and a controller configured to perform notification to a user when the short-distance communication with the first device is incapable of being performed.

Abstract: According to an aspect, an electronic device includes: a piezoelectric element; a first sound generating unit that is vibrated by the piezoelectric element and generates a vibration sound transmitted by vibrating a part of a human body; and a second sound generating unit that generates an air conduction sound.

Abstract: A charging terminal shortcircuit preventing circuit for a battery pack, capable of firmly preventing a shortcircuit and with employing a simple structure. In a battery pack so constructed that a charge current is supplied from a charger via a charging terminal to a battery, and a current is supplied from the battery via an output terminal to a portable appliance, and further the current from the charger via a through-input terminal and a through-output terminal to the portable appliance, there are provided a switch 22 for turning ON/OFF the charge current between the battery 21 and the charge terminal T.sub.4, and switch operating means for detecting an application of a voltage to the through-input terminal T.sub.6 to thereby turn ON the switch 22. Also, in a battery pack 2, a resistor having a large resistance value is connected parallel to the switch 22, and a battery pack mount detecting means of the charger 3 detects a voltage at the charging terminal T.sub.

Abstract: A malfunction preventing circuit for a battery charger of a two-terminal structure comprises charging terminals between which a battery is to be attached and connected; and an attachment detecting unit of a high impedance which detects a voltage across the charging terminals, thereby detecting the attachment of the battery, a circuit for connecting a low-impedance element to an output circuit of the battery charger via a switch is disposed, and means for, when an input power (AC power) for the battery charger is supplied, causing the switch to operate so that the low-impedance element is connected to the output circuit to lower the output impedance is disposed.