| 摘要 |
PURPOSE:To prevent a breakdown of fuse, load and so on by using a semiconductor switch as a switch for breaking the discharge current of a battery. CONSTITUTION:When connected normally, a transistor Tr1 is supplied with a base current by diode D1 and resistance R1 so as to be turned ON, a charging current is caused to flow through a battery B, and a load L is supplied with electric power. Also, when the battery B is discharged, the load L is supplied with electric power via diode D2. In this case, when the battery B is connected in a reversed polarity manner at the time of its exchange, said reversed polarity is detected by resistances R2 and R3 and a transistor Tr2 is reversely biased so as to be turned OFF to stop supplying the transistor Tr1 with a base current. Thus, when the battery B is connected reversely, a discharge current is little and its operating time is short so that a fuse and a load never break down. |
