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Parallel and Series Circuits

1. Why are batteries sometimes installed as parallel circuits and other times installed as series circuits?

2. What affects the way batteries are positioned? What are the benefits for the different positions?

3.How does electricity work together with magnetism? How are the two connected?

4. What are some examples of practical uses for magnetism?

5. What kinds of technologies in the real world can use inductance? How are these kinds of technologies affected by inductance?

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1. According to the desired voltage, current, and capacity, batteries are installed as parallel and series configurations. Battery packs get their desired operating voltage by connecting several cells in series. If higher capacity and current handling are required, the cells are connected in parallel. Some packs have a combination of serial and parallel connections. A laptop battery may have four 3.6-volt lithium-ion cells connected in series to achieve 14.4 V and two cells in parallel to increase the capacity from 2000 mAh to 4000 mAh. Such a configuration is called 4S2P, meaning 4 cells are in series and 2 are in parallel.

2. The capacity of the connection, desired voltage and current in the circuit are affected by the different positions of the batteries. The different types of configurations are series, parallel, or combinations of series and parallel.

In a series connection, the positive terminal of one battery is connected to the negative terminal of another battery, and the total voltage of the system is the sum of all the voltages. Another thing is that the current in the circuit will be the same as the current in any of the individual cells. In a 12 V battery pack, for example, there are 6 cells, with a potential difference of 2 V each. But the total current will be 1000 mA, which is the current associated with a single cell. Hence the capacity is also low.

In a parallel connection, the positive terminal of each cell is connected to the positive terminals of the other cells, and similarly with the negative terminals. The total voltage will remain the same, but the current increases as the number of cells increases. To obtain higher ampere-hour (Ah) ratings, two or more cells are connected in parallel. For example, connecting four cells of 2 V and 1000 mA in parallel means the voltage of the circuit is 2 V and has a current of 4000 mA. Hence the capacity is also increased. A high resistance or open cell is less critical in a parallel circuit than in a serial configuration, but the parallel pack will have a reduced load capability and a shorter runtime.

The serial/parallel connection allows good design flexibility and attains the wanted voltage and current ratings by using a standard cell size. The configurations will not affect the overall power but will provide the most suitable voltage and current source for the application.

3. Electricity can be static, which is caused by stationary charges, or dynamic, which is caused by ...

Solution Summary

This response compares parallel and series circuits, the relationship of magnetism to electricity and the uses of inductance.