A secondary cell is a rechargeable battery which can be charged, discharged into a load, and recharged many times, as opposed to a disposable or primary cell, which is supplied fully charged and discarded after use. The chemical reaction in a secondary cell is reversible and it has low internal resistance. It can supply both low current and high current. Example: Li-H Battery, Nickel-cadmium (NiCd) battery, lead storage battery

Epilepsy is a central nervous system (neurological) disorder in which brain activity becomes abnormal, causing seizures or periods of unusual behavior, sensations and sometimes loss of awareness. Anyone can develop epilepsy. Epilepsy affects both males and females of all races, ethnic backgrounds and ages.