Some Microcontroller based Laboratory instruments such as Digital balance, pH Meter etc have rechargeable battery inside. This inbuilt battery should be properly charged for the error free operation of these instruments. If the instrument is not using (or charging) for long time, its inbuilt battery will be destroyed permanently. This timer circuit helps to keep the battery in top condition through automatic charging for 5 to 6 hours daily so that the instrument can be left unattended. The battery will be charged only during the day time.
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