What circuit breaker acts as a switch creating an circuit when current is too high?

Answer 1

No. circuit breakers are in series with whatever lines they are protecting. They are never put in parallel with the protected loads (this would defeat the purpose).

Circuit breakers open resulting in an open circuit / no power to outlets when they trip.

Answer 2

A circuit breaker acts as a switch creating an open circuit when current is too high.

A circuit breaker in your house does exactly that. When current reaches a specific level above whatever the circuit breaker is rated at (10amps, 15amps, 20amps), the circuit breaker will "trip".

Physically, a circuit breaker looks similar to a light switch mounted sideways in your breaker panel. When it trips, the little lever moves to the open position. Often (perhaps always?) you must pull the lever back all the way to the open position before you can close it properly. The tripped position is somewhere between the two (open and closed).

The purpose of these circuit breakers are to isolate outlets that have a fault on them (dropped a hair dryer in the bathtub full of water), or due to overload (hooked up a hair dryer, space heater, oven, microwave, vacuum cleaner, and sound system to one outlet). Overload results in too much current flowing through wiring in your walls; this wiring will overheat when too much current flows, potentially resulting in a fire.