Spanningsbegränsare

Spanningsbegränsare, often translated as voltage limiter or surge protector, is a device designed to protect electrical and electronic equipment from damage caused by overvoltage or voltage surges. These surges can be caused by various sources, including lightning strikes, power grid fluctuations, or switching operations within the electrical system. The primary function of a spanningsbegränsare is to divert excess voltage away from sensitive connected devices, thereby preventing burnout or malfunction.

The most common type of spanningsbegränsare utilizes a Metal Oxide Varistor (MOV). An MOV is a semiconductor device with a resistance that varies significantly with applied voltage. Under normal operating voltages, the MOV has a very high resistance, allowing current to flow unimpeded to the connected equipment. However, when the voltage exceeds a specific threshold, the MOV's resistance drops dramatically, creating a low-impedance path that shunts the excess voltage to ground. This rapid response effectively shields the protected device from the damaging surge.

Spanningsbegränsare are found in a wide range of applications, from small household power strips protecting computers and televisions to large industrial installations safeguarding critical machinery. They are an essential component in ensuring the longevity and reliable operation of electrical and electronic systems. The effectiveness of a spanningsbegränsare is often rated by its ability to absorb a certain amount of energy, typically measured in joules, and its clamping voltage, which is the maximum voltage that will be allowed to pass through to the protected equipment. Regular inspection and eventual replacement of older units are recommended as MOVs can degrade over time with repeated surge events.