What is the difference between a fuse and a circuit breaker?

Both protect against overcurrent, but fuses are sacrificial devices that melt and must be replaced after operation, while circuit breakers can be reset and reused. Fuses are typically cheaper, simpler, and faster-acting for high fault currents. Circuit breakers offer remote operation capability, adjustable settings, and are more economical over time for frequently tripping circuits. Fuses are preferred for extremely high fault currents; breakers dominate in modern installations.