Transientspänningsskydd

Transientspänningsskydd, often abbreviated as TVS, refers to devices designed to protect electronic circuits from voltage transients. These transients are sudden, short-duration surges in voltage that can significantly exceed the normal operating voltage of a circuit. They can be caused by various sources, including lightning strikes, electrostatic discharge (ESD), switching operations in power systems, and inductive load switching.

The primary function of a TVS device is to divert the excessive energy of a transient away from the sensitive components of the circuit. They act as a voltage-dependent resistor, exhibiting very high impedance at normal operating voltages, thus having minimal impact on the circuit. However, when a transient voltage exceeds the TVS's clamping voltage, its impedance rapidly drops, effectively creating a low-impedance path to ground. This diverts the surge current, clamping the voltage to a safe level and preventing damage to downstream components.

TVS diodes are the most common type of TVS device. They are semiconductor devices that are designed to clamp transient voltages. They are characterized by their breakdown voltage, clamping voltage, and response time. Different types of TVS diodes exist, including unidirectional and bidirectional variants, to suit various circuit protection needs. Unidirectional TVS diodes are designed to protect against transients in one direction, while bidirectional TVS diodes can protect against transients in both positive and negative directions.

The selection of a TVS device depends on several factors, including the expected transient voltage levels, the circuit's operating voltage, and the required level of protection. Proper application of TVS devices is crucial for ensuring the reliability and longevity of electronic equipment.