# 1. Fundamentals of TVS and Protection Physics

## TVS Protection Principle

A TVS device limits voltage by entering avalanche conduction.

\[
V = V_{BR} \quad \text{(Avalanche region)}
\]

---

## Snapback Concept

Some protection devices exhibit snapback:

- Trigger voltage: \( V_{t1} \)
- Holding voltage: \( V_h \)
- Negative differential resistance region

---

## Dynamic vs Static Behavior

Static I-V does not fully describe ESD events.

Transient behavior dominates.