V18MLE0805LH Circuit Protection

TVS - Varistors, MOVs

The V18MLE0805LH is an 8mm leadless, surface mount Varistor. Varistors (also referred to as MOVs) are clamping (transient voltage suppression) devices which are used to protect sensitive circuits from voltage transients which can cause damage. Varistors are typically rated based on their undesirable but necessary ability to reliably absorb energies of up to hundreds of joules. The V18MLE0805LH is rated for up to 420 joules and operates at up to 250 VAC.

Application field

Varistors, like the V18MLE0805LH, are very suitable devices for circuit protection. Applying these Varistors as overvoltage protection ensures that the sensitive components in the circuit are not damaged in case of an overvoltage event. The specific area in which such Varistors are most widely used is the field of telecoms and datacom applications. In such applications, Varistors are mainly used to ensure that the communication system is effectively shielded from any overvoltage transient events.

Working principle

Varistors are non-linear resistors which work on the principle of clamping or diverting high voltage surges onto suitable ground levels, thus protecting the sensitive components present in the circuit. In the case of the V18MLE0805LH, there is a composed silicon carbide chip housed in its casing. Varistors, when subjected to a voltage surge, contain conducting channels which reduce the level of resistance and even turn it into a short circuit. This phenomenon is known as the avalanche effect and is crucial for the Varistor’s functioning. This effect varies widely between different Varistors. The V18MLE0805LH Varistor, due to its avalanche effect, is capable of accepting up to 420 joules of energy (at 250 VAC).The most important factor to consider while working with Varistors is finding an appropriate one which can cater to the specific application. Although Varistors can work for a wide variety of applications, the designer or engineer needs to consider the type of Varistor, the surge current rating and the size/package of the Varistor.

Hence, the V18MLE0805LH Varistor can be used as an effective device for circuit protection. As previously established, they are mainly used in telecommunication and datacom applications. Its high joules rating is suitable for such fields as telecoms and datacom, in which reliable and robust protection is essential. Additionally, its compact 8mm leadless design makes the V18MLE0805LH more suitable for applications in which high power surge protection is necessary.