
14 D.c. supplies
14.1 Introduction
Chapter 1 referred to the sources of d.c. supplies.
The primary battery, of which the Leclanche cell is an example, is
used extensively in portable electronic equipment. It is often called
a 'dry battery', and is discarded when exhausted.
The secondary battery, of which the nickel-cadmium cell is an
example, can be recharged when exhausted, and these cells can last
up to 15 years if handled with care.
Another source of supply is the solar cell which converts light
directly into electrical energy. The selenium cell is the best known
example.
Batteries can be connected in series and in parallel. Batteries hav ...