Battery size is indicated by letter designation. AA, AAA, C and D batteries all differ in size. They are designed for use in different types of battery-operated devices. The AA and AAA batteries, like C and D batteries, carry the same amount of voltage. The difference, however, is in the way the voltage is delivered.
The most obvious difference between AA and AAA batteries is their size. The AA cell battery is slightly longer than the AAA battery and is also somewhat wider. The C cell battery is larger than the AA battery, and the D battery is larger than the others.
Battery size determines the amount of current available. The D cell batteries give more current than the C cell batteries, and the AA cell batteries give more current than the AAA cell batteries. Because of the size difference in the batteries, AAA batteries hold a smaller amount of material than AA batteries. Appliances that require more power take larger-size batteries.
The AAA batteries are designed for use in small, low-power, mostly portable devices. Remote controls and clocks are typical examples. The AA batteries are designed to be used in devices that consume more power, such as battery-operated toys and small electric flashlights.
According to the University of Illinois Department of Physics, AA and AAA batteries, as well as C and D batteries, all have 1.5 volts. Voltage is a measure of the electrical potential in a source. It is also the force of the battery's supply of electricity.
Current is the flow of electricity through a conductor. It can be compared to the amount of water flowing down a pipe. The larger the current, the more water, or electricity, is flowing. Some electrical devices need more current, and larger batteries supply more current. Voltage and current are equally important factors in batteries and other electrical devices.