Abstract: According to one embodiment, an extension apparatus includes, a housing, a hook portion, a switch portion, a mechanical portion which moves the hook portion between the engaged state and the disengaged state, a pin portion provided inside the switch portion, a first spring portion interposed between the housing and the pin portion, an abutting portion provided in the mechanical portion, abutting a distal end of the pin portion, and releasing abutment when the pushing amount of the switch portion exceeds a predetermined amount, and a second spring portion striking the distal end of the pin portion against a sound-producing portion when abutment of the distal end of the pin portion is released.

Abstract: According to at least one embodiment, the embodiment provides a method for determining a size of an electronic apparatus. The electronic apparatus includes a connector for electrically connecting to an external apparatus, and a supporting plate for supporting a back surface of the external apparatus. The method includes determining a minimal length of the electronic apparatus by balancing moment of forces on a first fulcrum according to a first acting force, a gravity of the external apparatus and a length of the external apparatus in a condition that the external apparatus does not rotate with respect to the electronic apparatus.

Abstract: According to one embodiment, the electronic apparatus includes a main body including a main body connector, a holder detachably mounted on the main body, the holder including a front supporter and a back supporter that are used to support an external apparatus and an opening between the front supporter and the back supporter, the main body connector exposed from the opening when the holder is on the main body, so that an external apparatus connector of the external apparatus is plugged to the main body connector to achieve an electrical connection when the external apparatus is inserted between the front supporter and the back supporter.

Abstract: According to one embodiment, an extension apparatus includes, a housing, a hook portion, a switch portion, a mechanical portion which moves the hook portion between the engaged state and the disengaged state, a pin portion provided inside the switch portion, a first spring portion interposed between the housing and the pin portion, an abutting portion provided in the mechanical portion, abutting a distal end of the pin portion, and releasing abutment when the pushing amount of the switch portion exceeds a predetermined amount, and a second spring portion striking the distal end of the pin portion against a sound-producing portion when abutment of the distal end of the pin portion is released.

Abstract: According to at least one embodiment, the embodiment provides a method for determining a size of an electronic apparatus. The electronic apparatus includes a connector for electrically connecting to an external apparatus, and a supporting plate for supporting a back surface of the external apparatus. The method includes determining a minimal length of the electronic apparatus by balancing moment of forces on a first fulcrum according to a first acting force, a gravity of the external apparatus and a length of the external apparatus in a condition that the external apparatus does not rotate with respect to the electronic apparatus.

Abstract: According to one embodiment, the electronic apparatus includes a main body including a main body connector, a holder detachably mounted on the main body, the holder including a front supporter and a back supporter that are used to support an external apparatus and an opening between the front supporter and the back supporter, the main body connector exposed from the opening when the holder is on the main body, so that an external apparatus connector of the external apparatus is plugged to the main body connector to achieve an electrical connection when the external apparatus is inserted between the front supporter and the back supporter.