4.2.2 Leclanché cell
The most common type of primary cell in use is the Leclanché cell. In its wet form, it consists of a glass jar containing:
- a saturated solution of sal ammoniac (ammonium chloride) as the electrolyte,
- a zinc rod as the negative electrode, and
- a plate of carbon as the positive electrode.
4.2.2.1 Wet Leclanché Cell
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| Wet Leclanché cell |
A mixture of manganese dioxide and powdered carbon is pressed around the carbon rod and then enclosed in a porous pot which the solution can soak through. The manganese dioxide acts as the depolarizer, while the powdered carbon gives greater conductivity.
The e.m.f. of the Leclanché cell is 1.5 V and the internal resistance of a normal size cell is 1 Ohm. The wet cells are now going obsolete. They were once a majorly used to supply power to land-line telephone installations in remote areas.

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