THE RECORD
What changed
Bardeen, Brattain and Shockley's Bell Labs team demonstrated a point-contact transistor in 1947; junction and silicon devices followed.
EVIDENCE
What remains
Notes, patents, devices and manufacturing records trace discovery to mass production.
WHY IT MATTERS
Why it matters
It became the basic unit of digital circuits from radios to smartphones.
OPEN QUESTION
Where interpretation begins
It depended on quantum physics, materials and manufacturing, not one instant by three men.