This article describes the difference between a fuse and a circuit breaker. An electric circuit is defined as a closed path consisting of various electrical devices such as resistors, capacitors, etc. across which electric current flows. The electric circuit has an electric current generating source such as a battery that drives the operation of the connected circuit.
Fuses and Circuit Breakers play a key role in electrical and electronic circuits by restricting the flow of excess current in the electric circuit. In this article, the important differences between fuse and circuit breaker will be highlighted along with a basic definition of each.
What is a Fuse?
Fuse is an electronic safety device that protects the circuit from getting overheated due to the excess flow of current in the electric circuit. A fuse is comprised of a metallic materials such as tin and lead, glass, plastic, etc.
The fuse works in an electric circuit by detecting faults or current overflow in the circuit resulting in the meltdown of the metallic material of the fuse. This meltdown of the metallic material results in the disconnection of the circuit. This in turn safeguards the other electronic devices that were a part of the electronic circuit. The detached fuse is then replaced with another one or wired back to the electric circuit.
The main function of a fuse in the circuit is to provide protection of the circuit from damage due to current overflow. The major causes of excessive current in an electric circuit include short circuit connection, failure or damage of electronic devices in the circuit, overloading, etc.
What is a Circuit Breaker?
A Circuit Breaker is a protective and switching device that safeguards the circuit from damage to the circuit components due to major faults in the circuitry. Circuit breaker functions like a switch that trips on detecting failures in the circuit elements. Circuit breakers are either manually operated or automated. The main reason that makes a circuit breaker preferable as compared to a fuse is that it need not be replaced, but it can be reset to be used in the circuit again.
Circuit breakers are used in applications involving heavy mechanical loads having high current requirements. Besides the protection of the electric circuit from current overflow, circuit breakers also shield the circuit from other electronic problems such as high voltage, circuit overloading, short-circuiting, etc. Additionally, circuit breakers find their applications as switches in an electronic circuit besides circuit safety.
Difference Between Fuse and Circuit Breaker
The table below lists the main differences existing between a fuse and a circuit breaker as follows.
| Parameter | Fuse | Circuit Breaker |
| Definition | A fuse is a protective device that prevents current overflow in an electronic circuit. | A circuit breaker is also a protective device that shields the electric circuit from damage due to faults, short circuits, high voltages, etc. |
| Symbolic representation |  |  |
| Principle of operation | A fuse works by melting the metallic material inside of it, based on its thermal and electrical characteristics, when excessive current flows through the circuit. | A circuit breaker operates based on the concept of internal switching. It trips and disconnects the circuit when a fault, current, or voltage overflow and overloading is detected in the electric circuit. |
| Switching phenomenon | A fuse operates based on melting phenomena and does not involve any kind of switching. | Circuit breakers involve internal switching phenomena. |
| Mode of operation | A fuse can function only in an automated fashion. | A circuit breaker can function in a both manual and automated manner. |
| Duration of working | A fuse operates for a shorter interval of time i.e., for just about 0.002 seconds. | A circuit breaker works for a longer duration ranging between 0.02 and 0.05 seconds. |
| Functionality | A fuse performs the function of both identifying and interrupting the fault occurrences in an electronic circuit. | A circuit breaker only performs the function of interrupting the electric current flowing in the circuit. While the fault identification is done by a relay. |
| Usability | A fuse can be utilized only once in an electronic circuit after which it has to be replaced by a new one. | A circuit breaker can be utilized several times even after using it once in an electric circuit. |
| Curve behavior | The property curve of a fuse shows fluctuations due to aging. | The property curve of a circuit breaker remains constant. |
| Break down capability | The breakdown capacity of a switch is comparatively lower. | The breakdown capability of a circuit breaker is comparatively higher. |
| Construction | The fabrication of a fuse is relatively simpler. | The fabrication of a circuit breaker is relatively complex. |
| Expense | The price of a fuse is comparatively much reasonable. | The price of a circuit breaker is comparatively expensive. |
| Applications | A fuse safeguards the smaller circuits involving low current usage, against current overflow and overloading issues. | A circuit breaker safeguards heavy machinery having extensive current requirements. |
Conclusion
In conclusion, this article provided detailed information on fuse and circuit breakers in an electronic circuit and how each one operates in order to protect the circuit components from getting damaged. Although both the fuse and circuit breaker are safety devices, they have some notable differences between them as highlighted in this article. The major difference existing between these two components is that a fuse functions by melting down the metallic element inside of it in order to disconnect the circuit, while a circuit breaker protects the circuit by turning down the internal switch present in it.