Remember to read the intro.
Do not confuse this with the failure rate circuit breaker. This one is actually closer to the concurrency circuit breaker. But instead of counting concurrency it counts number of requests made in a time period. Once the limit is reached for the current time period all requests after that are failing until a new time period is started.
Similar to the concurrency circuit breaker this one detects problems fast and if the time period used is short it recovers fast. It also handles uneven load much better than the pure concurrency based breaker.