However, for a battery to be of practical
use it should be reasonably light, compact and its voltage should not
vary appreciably during its use There are mainly two types of batteries In the primary batteries, the reaction occurs only once and after use
over a period of time battery becomes dead and cannot be reused
again The most familiar example of this type is the dry
cell (known as Leclanche cell after its discoverer) which is
used commonly in our transistors and clocks