Fuses and circuit breakers are both used to protect electrical systems from overloads or short circuits, but they operate differently. Fuses work by melting a metal filament when the current exceeds a certain level, whereas circuit breakers use an electromagnet or bimetallic strip to trip the switch and break the circuit. Fuses must be replaced after they blow, while circuit breakers can be reset after the trip. Circuit breakers are more commonly used in modern electrical systems due to their convenience and ease of use, while fuses are still used in some older systems or for specific applications.