Transient-voltage-suppression diode
A transient-voltage-suppression (TVS) diode, also transil, transorb or thyrector, is an electronic component used to protect electronics from voltage spikes induced on connected wires. == Description == The device operates by shunting excess current when the induced voltage exceeds the avalanche breakdown potential.
Source: Wikipedia — Transient-voltage-suppression diode (CC BY-SA 4.0)