A series circuit is defined as a circuit having two or more

components connected end to end to form only one path for current

flow.

In the hydraulic system shown above, when fluid is flowing out of the

pump at the rate of three gallons per minute, fluid must be flowing

into the other side of the pump at the rate of three gallons per

minute. Therefore, the rate of flow of fluid throughout the system

must be constant. Similarly, this same concept is true regarding

current flow in the series circuit shown below. When current is

flowing out of the negative terminal of the battery at the rate of

three amperes, the current flowing into the positive terminal to the

battery is at the same rate, or three amperes.