When combined in a circuit, what is the purpose of using a buffer?

The function of a buffer in a circuit is primarily to increase current without changing voltage. This characteristic is fundamental because buffers isolate different parts of a circuit, allowing one component to drive another without affecting the original signal's characteristics. Buffers ensure that a load connected to their output does not draw excess current from the preceding stage, which helps prevent distortion in the signal being transferred. They can also provide impedance matching, which further protects the integrity of the signal.

For example, if a circuit is designed to output a weak signal that needs to activate a heavier load, a buffer can amplify the current capacity, enabling the load to be powered effectively while keeping the voltage levels stable and unchanged. This plays a crucial role in digital circuits where signal integrity and logic levels must be maintained throughout the design.

The other choices relate to different circuit functions: storing energy is more relevant to capacitors or inductors, switching signals typically refers to transistors or other types of switches, and logic level inversion is achieved through specific logic gates (like NOT gates) that perform a different operation altogether.