Overdamped vs Underdamped JJ Lab

McCumber β_C sorts personality: ≲1 → short pulse then V≈0 (RSFQ); ≫1 → latches until reset (I/O / drivers). Same trigger, different outcome.

β_C (cartoon) 0.8

β_C = 2π I_c R² C / Φ₀ ···

Regime

overdamped

After kick

pulse → V≈0

State

ready

RSFQ-safe?

YES

I/O latch tool?

V(t) after kick · shaded area ≈ Φ₀ only for a clean overdamped slip

Drag β_C across ~1. Overdamped = screen door that stops. Underdamped = door that stays open until you pull it shut.