Primary Cell

Primary Cell Points : Primary Cell, Types of Primary Cell, Voltaic cell, Daniel cell, LecLanche cell, Dry cell, Construction Definition Cell whose working does not depend upon any external source is called primary cell.

Types of Primary Cell 1. Voltaic cell
2. Daniel cell
3. LecLanche cell
4. Dry cell 1. Voltaic cell It consists of glass vessel filled with sulphuric acid and in which a zinc and a copper strip is placed. The two strips are connected by a conducting wire. Zinc plate has negative charge called cathode and copper plate has positive charge called anode.

Working When Zinc strip placed in acid solution it is attached by the acid and begins to dissolve Zinc atoms enter in the solution as Zn⁺² ion and released two electrons on the strip. 2. Daniel Cell It consists of a Copper vessel act as anode filled with saturated copper sulphate solution. Amalgamated Zinc rod is placed in a porous pot situated in the centre and act as cathode.

Working Zinc atom enters in the solution as Zn⁺² ion and release two electrons on the rod. Hydrogen positive ion gain electron from copper as a result hydrogen becomes neutral and copper container becomes positive. 3. LecLanche Cell It consists of a positive carbon electrode packed into a mixture of Mn0₂ and powder carbon in a porous pot. The negative Zinc electrode dipped in standard solution of NH₄ CI.

4. Dry cell It is modified by LecLanche Cell.

Construction It consists of a Zinc container act as negative electrode tl1ed with a paste of ammonium chloride, manganese dioxide, powder carbon and water. A carbon rod is placed in the centre and act as positive electrode. Use They are use in touches radio sets and transistors appliances.