Also known as “double A”, AA batteries are by far the most popular battery size. Used in a multitude of applications, these batteries can be purchased almost anywhere. Double A batteries are generally what everyone pictures when they think of standard replaceable batteries. AA batteries measure at 1.5V.

Also known as “triple A”, AAA batteries are the second most popular kind of battery. Triple A batteries are often used for small electronic devices such as TV remote controls, kitchen timers, graphing calculators, and bathroom scales. AAA batteries, like AA batteries, also measure at 1.5V, but generate less energy due to their smaller size.

A single cell is not sufficient for some devices. To achieve desired voltage, the cells are connected in series to add the voltage of cells. To achieve the desired capacity, the cells are connected in parallel to get high capacity by adding ampere-hour (Ah). This combination of cells is called a battery.

The series configuration is used where the voltage of a single cell is not sufficient. The series configuration is achieved by connecting the positive of a cell to the negative of another cell.

The cells are connected in parallel to fulfill higher current capacity requirements if the device needs a higher current but there is not enough space available for the battery. That device can use the parallel configuration to fit high-current capability in a small space.

AC is also called mains electricity, household current, domestic power, line power, or wall power because it is the voltage supplied by a wall outlet. Worldwide, AC voltages range from 100 to 240 V. The rate of direction change is typically 50 to 60 times per second and is designated as Hertz (Hz).

In the NZ, the mains voltage is approximately 230V. It is an alternating current (a.c.) supply. This means the current is constantly changing direction. In the NZ, it has a frequency of 50 hertz (Hz) which means it changes direction and back again 50 times per second.

Alternating current (A.C) is five times more dangerous than Direct current (D.C). The frequency of the alternating current is the main reason for this severe effect on the human body. The frequency of 60 cycles is in an extremely harmful range. At this frequency, even a small voltage of 25 volts can kill a person.

The main factor that went into the choice of AC over DC was that AC is more efficient. Its ability to travel back and forth made gave it the ability to travel over longer distances. Thus making it able to power more homes.

Limiting current flow in the human body to safe levels is entirely dependent on the resistance of the short-circuiting jumper. To achieve this safe current level the voltage across the human body must not exceed 100 volts.