114 Electricity & Electronics Notice that the voltage has increased four times. However, the capacity of the battery to supply a current is the same as one cell. Cells are connected in this manner to supply higher voltages for many uses. A fl ashlight may use two or more cells in series. Batteries for portable equipment have many cells in series to produce 6, 9, or 24 volts. Th e amperage does not increase by connecting cells in series. Parallel Connection In Figure 7-13, the positive terminals have been connected together, and the negative terminals have been connected together. Th ese cells are connected in parallel. Th e total voltage across the terminals of the battery is the same as one Schematic Symbols 6 Volts 1 Ampere – Flashlight Cells 1.5 V @ 1A 1.5 V @ 1A 1.5 V @ 1A 1.5 V @ 1A Goodheart-Willcox Publisher Figure 7-12. Pictorial and schematic diagram of four cells connected in series. Voltages add when connected in series. Voltages in Parallel In this experiment you will demonstrate and observe how voltages add in parallel. MATERIALS ■ 4 fl ashlight cells (D-type) ■ 4 cell holders ■ 1 multimeter PROCEDURE 1. Connect the four cells in parallel. See the schematic in Exhibit 7-2A. 2. Set your multimeter to read voltages in the 0 V to 10 V range. 3. Measure and write down the voltage between points A and B. 4. Remove cell #4. Measure and write down the voltage between points A and B. 5. Remove cell #3 (do not replace cell #4). Measure and write down the voltage between points A and B. 6. Remove cell #2 (do not replace cells #3 or #4). Measure and write down the voltage between points A and B. Do your results follow the formula for voltage sources in parallel? What conclusion can you draw from this experiment? E x p e r i m e n t 7 - 2 A B Cells #1 #2 #3 #4 − + − + − + − + Goodheart-Willcox Publisher Exhibit 7-2A Copyright Goodheart-Willcox Co., Inc.