Abstract: A rechargeable battery is utilized in many kinds of electrical appliances. However, as the battery contains harmful substances such as cadmium, it is not desired to discard the electrical appliances with the rechargeable battery from a standpoint of prevention of environmental pollution. An electrical appliance powered by an incorporated rechargeable battery of the present invention is capable of effectively engaging a tool for separating the battery from the appliance. That is to say, at least one of negative and positive electrodes of the rechargeable battery is connected to a terminal strip by spot welding. An electrical power of the battery is supplied to a circuit for operating the appliance through the terminal strip. The terminal strip also has an opening which is formed so as to engage a tool for separating the battery from the terminal strip.

Abstract: An improved battery charger for charging a battery from a dc power source includes a DC-to-DC converter comprising a transformer and a switching transistor connected in series with the primary winding of the transformer. The transformer has its primary winding connected to the dc power source and has its secondary winding connected to the battery to be charged. The switching transistor is controlled to be alternately turned on and off in order to develop across the secondary winding an induce voltage which is rectified to be applied to the battery for charging the same. The secondary winding of the transformer is electrically connected to the dc voltage source in such a manner that the induced voltage of the transformer is in an additive relation with the terminal voltage of the dc voltage source.

Abstract: A portable type electric appliance powered by incorporated main and reserve batteries. The batteries are connected to an electric load selectively by means of a switching device including a main switch for connecting the main battery to the load and a subsidiary switch for connecting the reserve battery to the load. A lock locks the subsidiary switch in a disconnected position until the main switch is closed. Namely, the subsidiary switch can be closed only after the main switch is closed. Therefore, the main battery is always used prior to the reserve battery, and when the main battery is exhausted, the reserve battery remaining unexhausted is capable of taking over to operate the appliance without requiring immediate replacement of the main battery. Accordingly, the accidental interruption of the operation of the appliance can be avoided.