A circuit breaker for a low-voltage circuit is disclosed. In an embodiment, the circuit breaker includes a current conductor, assigned a measuring transducer for measuring the electrical current of the current conductor; a first filter connected to the measuring transducer; an analog/digital converter connected to the first filter; a second, high-pass filter connected to the analog/digital converter; and a digital integrator, connected to the high-pass filter and configured to determine the electrical current of the current conductor.