General Certificate of Secondary Education (GCSE) Design Technology Practice Exam

The primary function of capacitors in circuits is to store charge for a period of time. Capacitors are passive electronic components that can accumulate electrical energy in an electric field when voltage is applied across their terminals. This stored energy can then be released back into the circuit when needed. This ability to store and release energy makes capacitors crucial in various applications, such as smoothing out voltage fluctuations in power supply circuits, filtering signals in audio equipment, and timing applications in oscillators.

While capacitors can play roles in regulating voltage levels and filtering, they do not inherently generate power or provide insulation, which are functions associated with other components like power supplies and insulators, respectively. Thus, the correct identification of their main function as a storage device highlights their essential role in managing electrical energy within circuits.