BATTERY CHARGER

摘要

A battery charger outputs a high voltage even when the charger is not connected to a power unit provided with a rechargeable battery so that the charger can apply a high voltage to the power unit when the power unit is connected to the output terminal. The charger is provided with a periodic signal generating means which supplies a periodically changing periodical signal to the output terminal and a detecting means which judges whether or not the charger is connected to the power unit by detecting the periodic signal at the output terminal. Therefore, the battery charger can recognize the connecting state of the power unit even when the charger is provided with no mechanical switch.