Cell or HHO Cell or Electrolyzer Cell is defined as one unit in an electrolysis system (a series of individual cells). By a certain arrangement of electrodes (when plates are used), a single device can have several cells.
It is a device used for generating an electromotive force (voltage) and current from chemical reactions. In HHO production the cell is very similar to a battery cell, except instead of producing electricity, it produces HHO. Many Shapes and Styles are in use with Hydrogen on demand systems, many actually look like a multi cell battery. In fact most cells using catalyst will show a degrading voltage across the terminals when power is removed. The number of cells in a HHO generator determine the efficiency of the unit because the more cells used the voltage is spread out further.