Abstract: A display/response system includes a show display apparatus and a response apparatus. In the show display apparatus, a show and a questionnaire are received, and the show is displayed. The questionnaire is sent to the response apparatus. The response apparatus displays a screen for the received questionnaire, determines a response to the questionnaire in response to an operation, and returns the response to the show display apparatus. The show display apparatus returns the response received from the response apparatus to a response collection apparatus.

Abstract: A display/response system includes a display/response apparatus and a display apparatus. A show and a questionnaire are received by the display/response apparatus, and the show is immediately displayed on the display/response apparatus. The questionnaire is sent to the display apparatus and displayed on the display apparatus. In the display/response apparatus, a response to the questionnaire displayed on the display apparatus is determined in response to an operation, and the determined response is sent to a predetermined response collection apparatus.

Abstract: A booster type DC-DC conversion circuit and a voltage reduction type DC-DC conversion circuit are connected in series with a battery. When battery voltage is high, the booster type DC-DC conversion circuit does not operate, and the voltage reduction type DC-DC conversion circuit outputs a constant voltage lower than the battery voltage. When the battery voltage drops, the booster type DC-DC conversion circuit operates, and converts the battery voltage to a constant voltage higher than the operation voltage of the voltage reduction type DC-DC conversion circuit. The voltage reduction type DC-DC conversion circuit outputs a constant voltage. The power supply apparatus can continuously output a constant voltage from when the battery voltage is high until it becomes low, and can efficiently utilize the battery capacity.