What are circuit breakers primarily used for?

Circuit breakers are primarily used to protect electrical circuits from overloads and short circuits, which can lead to potential hazards such as equipment damage or fire. When excessive current flows through a circuit, the breaker automatically interrupts the electrical supply, effectively preventing damage to both the electrical system and connected devices. This safety feature is crucial for maintaining the integrity of electrical systems and ensuring the safety of users.

The other options do not accurately represent the function of circuit breakers. Increasing electric current or measuring electrical resistance pertain to different electrical components, such as amplifiers or ohmmeters, while converting AC to DC involves rectification processes, which are handled by rectifiers rather than circuit breakers.