3. Technical Basics
3c Primary and Secondary Cells
Battery v Cell
There is always a little confusion over the words "cell" and "battery".
Before you took up Amateur Radio as a hobby what you and I, and probably hundreds of others, thought of as a battery
is in fact a cell. Go into a shop and ask for a single 1.5 volt battery and
you will be sold a 1.5V battery but in fact what you will have bought is
a single 1.5V cell.
For Amateur Radio and this course especially you need to know that it is only when two or more cells are connected in series or parallel do
those cells become known as a battery. |
3c.1 Understand that cells store energy in chemical
form.
Cells have the ability to store electrical energy in the chemicals
which make up the cell, else they would be of
little use in a torch!
Recall that a primary cell, once discharged, must be
properly disposed of.
There are two types of cells - PRIMARY and SECONDARY.
The primary cell 1.5V is used once and then you must be properly dispose
of it !!
The primary cell has a typical voltage of 1.5V which can only be discharged
and then properly disposed.
Within the cell a chemical reaction takes place to provide the electrical
energy but this is a one way ticket for the electrons - they cannot be forced
back inside the battery.
Understand that a secondary cell is rechargeable as
the chemical reaction process which takes place within the cell is reversible.
The secondary cell 1.2V use and can be recharge a number of times but eventually
it too will need to be disposed of properly. !!
With the secondary cell the chemical reaction within the cell is reversible
a number of times by a process called "recharging" which does reverse the
chemical reaction. There is however a limit to the number of times this
process can take place and it must be carried out strictly in accordance
with the manufacturers recommendations.
You will probably know a secondary cell as a nicad ( nickle
cadmium ) or another is the nickel metal hydride as these are both
rechargeable cells, however the Nicad is becoming obsolete. |