20 Circuit Breaker Interview Questions and Answers

A circuit breaker is an important component of an electrical system. It is used to protect the system from damage by interrupting the flow of electricity when there is an overload. When applying for a position in electrical engineering, you may be asked questions about circuit breakers. Answering these questions correctly can help you demonstrate your knowledge and earn the job. In this article, we review some common circuit breaker questions and how to answer them.

Circuit Breaker Interview Questions and Answers

Here are 20 commonly asked Circuit Breaker interview questions and answers to prepare you for your interview:

1. What is a circuit breaker?

A circuit breaker is an electrical device that is used to protect against overloads and short circuits. It is designed to automatically open and close the circuit in order to prevent damage to the electrical system.

2. Can you explain the use of circuit breakers in microservices applications?

Circuit breakers are used to prevent cascading failures in microservices applications. When one service in an application fails, it can cause a ripple effect that takes down other services. Circuit breakers are used to isolate the failing service so that it does not take down the entire application.

3. How do circuit breakers work within an application that uses asynchronous code?

Circuit breakers are used to prevent cascading failures within an application. They work by monitoring for failures within the system and then automatically breaking the circuit, or stopping the flow of traffic, when a failure is detected. This prevents the failure from spreading to other parts of the system and causing further damage.

4. What are some different types of circuit breakers?

Some different types of circuit breakers are air circuit breakers, oil circuit breakers, and vacuum circuit breakers.

5. What’s the difference between reset, half-open and open states on a circuit breaker?

The reset state is the default state for a circuit breaker, and it means that the breaker is ready to accept current. The half-open state means that the breaker is allowing some current to flow, but not all of it. The open state means that the breaker is not allowing any current to flow.

6. What are some examples of situations where using a circuit breaker might be useful?

A circuit breaker can be useful in any situation where you want to be able to handle failures gracefully. For example, if you are making a call to an external API and you want to be able to handle the case where the API is down, you could use a circuit breaker. That way, if the API call fails, the circuit breaker will trip and prevent any further calls from being made, and your application can continue running without issue.

7. What happens when there is an error while running a task in a circuit breaker?

When an error occurs while running a task in a circuit breaker, the breaker “trips” and breaks the circuit. This prevents the task from running again until the breaker is reset.

8. How can you test if your circuit breaker is working as expected?

There are a few ways to test if your circuit breaker is working as expected. One way is to simply try to trip the breaker by overloading it with electricity. If the breaker trips and cuts off the power, then it is working as it should. Another way to test the breaker is to use a multimeter to test the continuity of the circuit. If the circuit is broken, then the multimeter will not register a continuity reading.

9. What are the advantages of using circuit breakers in microservices architecture?

Circuit breakers are used in microservices architecture to provide isolation between services. This isolation can help to prevent cascading failures and improve resilience. Additionally, circuit breakers can help to improve performance by allowing failed requests to be short-circuited instead of being passed through to the downstream service.

10. What are the disadvantages of using circuit breakers in microservices architecture?

The main disadvantage of using circuit breakers in microservices architecture is that they can introduce additional latency into the system. This is because each time a circuit breaker trips, it needs to wait for a certain amount of time before it can be reset. This can cause problems if the circuit breaker trips frequently, as it can add significant delays to the system. Additionally, circuit breakers can also add complexity to the system, as they need to be configured properly in order to work correctly.

11. Why should we not assume that our circuit breaker will always protect us from all possible errors?

The main reason why we should not assume that our circuit breaker will always protect us from all possible errors is because it is possible for the circuit breaker to fail. If the circuit breaker fails, then it will no longer be able to protect us from errors. Additionally, even if the circuit breaker does not fail, it is still possible for errors to occur. This is because the circuit breaker is not perfect and it can only do so much to protect us.

12. What are the best practices for developing with circuit breakers?

There are a few best practices to keep in mind when developing with circuit breakers:

1. Use circuit breakers to isolate failure points in your system.

2. Use circuit breakers to prevent cascading failures.

3. Use circuit breakers to improve system availability.

4. Use circuit breakers to improve system performance.

13. Is it possible to handle exceptions by implementing a circuit breaker design pattern in Java 8?

Yes, it is possible to handle exceptions by implementing a circuit breaker design pattern in Java 8. This can be done by using the CompletableFuture class and the handle() method.

14. What is the recommended timeout value for a circuit breaker?

The recommended timeout value for a circuit breaker is 1 second. This ensures that the circuit breaker will trip if there is a problem with the circuit, but that it will not trip if there is a temporary issue.

15. What are some ways to improve performance when using a circuit breaker?

There are a few ways to improve performance when using a circuit breaker:

– Use a faster-acting breaker. This will help to prevent problems before they start.
– Use a higher-rated breaker. This will help to handle more current without tripping.
– Use a breaker with a higher voltage rating. This will help to prevent voltage drop across the breaker.
– Use a breaker with a lower resistance. This will help to reduce power loss across the breaker.

16. Can you explain what latency means in the context of circuit breakers?

Latency is the time it takes for a signal to travel from one point to another. In the context of circuit breakers, it refers to the time it takes for the breaker to trip and cut off the flow of electricity. The faster the breaker trips, the less damage there will be to the electrical system.

17. What is a fallback function?

A fallback function is a function that is executed when a circuit breaker trips and the primary function is unavailable. The fallback function should be a simplified version of the primary function that can still provide some level of functionality.

18. How does a circuit breaker differ from a threshold or limit check?

A circuit breaker is designed to protect a system from overload by automatically disconnecting it from the power source when a certain threshold is reached. A limit check, on the other hand, simply monitors the system to see if it is approaching or exceeding its capacity so that corrective action can be taken before an outage occurs.

19. What are some real world scenarios where a circuit breaker can help?

A circuit breaker can help in many scenarios where there is a risk of overloading a system. For example, in an electrical grid, a circuit breaker can help prevent damage to the system by automatically disconnecting circuits when there is too much current flowing through them. In a computer system, a circuit breaker can help prevent overloading by disconnecting parts of the system that are not being used.

20. How do timeouts affect circuit breakers?

Timeouts can cause circuit breakers to trip if they are not properly configured. If a timeout is too short, then the circuit breaker may trip prematurely. If the timeout is too long, then the circuit breaker may not trip at all, which can lead to problems.