4.4 Circuit Diagram Symbols In a circuit diagram, the cells are represented by the symbols shown below. Electric cell symbol Two cells in series symbol Cells in series symbol The long, thin stroke represents the positive electrode; while the short, thick stroke represents the negative electrode of the cell. These are conventional symbols and the polarity marks (+ or -) may be omitted. Most electric cells source are 1.5 volts when new. This electric potential is too weak to deliver a large amount of electric energy. When this is needed, two or more cells are used. For example, a torch requires two size D cells to give enough light. But more powerful torches require three or four such units. Similarly, small radios require three size D cells, while the large ones require as many as twelve. In principle, the term battery refers to more than one cell when used or connected together. Consequently, the two dry cells in a torch form a battery just as the six dry cells in the radio. The i...