A reed switch is an electrical component that consists of two ferromagnetic contacts sealed within a glass tube. When a magnetic field is applied, the contacts close, allowing current to flow. This simple mechanism makes reed switches useful in various applications, such as in security systems, automotive sensors, and home appliances. Reed switches are known for their reliability and fast response time. They can be activated by a magnet without any physical contact, which reduces wear and tear. Their compact size and low power consumption make them ideal for use in smart devices and IoT applications.