What Are Circuit Protection Devices?

Electronics and electrical circuits are often sensitive to overload conditions, presenting the risk of component damage, short-circuiting, fire hazards, and other issues if excessive current is allowed to travel through a circuit uncontrolled. In order to protect devices from volatile current, circuit protection devices are commonly implemented. Circuit protection devices are simply voltage sensitive devices that provide protection against overcurrent and overvoltage conditions, and they can come in numerous forms depending upon the application and needs. In this blog, we will provide a brief overview of some common circuit protection devices, allowing you to better protect your electrical systems and appliances.

In general, circuit protection will vary depending upon the devices or appliances that are being protected. For home power, lighting, power supplies, HVAC systems, appliances, and other various commonly used systems, the circuit breaker is most often used for protection. A circuit breaker is a type of operated electrical switch, preventing damage to electronics resulting from excess current and overloads. When a fault is detected, circuit breakers are capable of tripping, ensuring that contacts are rapidly broken to deter the flow of current. Coming in a variety of forms, circuit breakers are fairly fast acting, and they are able to be reset at any time in order to resume standard operations. Thermal protector circuit breakers are a common type that takes advantage of a bimetal strip that deforms during overload conditions to trip the circuit.

For the protection of laptops, mobile devices, game systems, digital cameras, monitors, and other smaller devices, fuses are a commonly used device. While there are a number of fuses with varying forms of design, the most basic types consist of a metal wire or strip that will break down when a certain threshold of current flows through it. Rapidly acting, the fuse will prevent any current from flowing once the wire or strip has melted. Because of this method of protection, however, fuses are considered a sacrificial device and must be replaced every time that they break down. Nevertheless, their common availability and low price point often makes this drawback fairly unimportant in comparison to the protection that they provide.

Electrostatic discharge is a condition that can heavily damage sensitive components, coming in the form of energy transfers between objects that are differently charged. Diode arrays are a common form of ESD protection device that consists of several diodes placed in a single semiconductor package. These diodes will often share a common cathode of anode or will be separate, and types will typically be chosen based on the required number of channels, maximum breakdown voltage, capacitance, and more. Generally, such protection devices may serve scanners, flashlights, USB power applications, integrated circuits, WAN equipment, and more.

If switching and controlling current is a desire, then the power thyristor is also a good option. Coming in the form of a solid state component that acts as a toggle switch, the power thyristor can benefit high current flow applications. When receiving a specific voltage on their gate terminal, current will begin conducting even when voltage ceases. This allows them to act as a current control device, providing a wide power rating range.