這張電路圖的連結網站如下: http://www.circuitstoday.com/tag/battery-charging-indicator
請看原文的解釋:
This simple circuit can be used to monitor whether a battery is charging or not. The voltage comparator IC LM393 is the heart of this circuit. The LED D1 will remain ON whenever there is at least 25 milli ampere current flowing to the battery. This particular circuit is designed for a 12V battery with charging current less than 1A.By slightly modifying the component values, the charging current and voltage can be modified.
其中說道:當電流持續對電瓶充電小於 25 milli(毫) 安培時,LED燈會持續發亮,這個電路圖是對12V小於1A的電流所設計?(奇怪,我的檔位都調到3~4A耶),充電的電壓與電流可以被修改。