This page describes the IBM SMS card "NLWT", and is part of the SMS card database.

Function of the card:
CTDL Emitter Follower NPN

Complemented Transistor Diode Logic (CTDL) is IBM's term for a form of diode-transistor logic.

Part number: 371632

Cap code: WT (details)

Symbol: DE

DE: Driver Emitter Follower. A driver, operating on the emitter follower principle, used for power amplification, impedance matching, and isolation without inversion. Often used as a logical element.

References: IBM Standard Modular System, Component Circuits, p232
SMS Cap Code Templates & Index

The information on these pages comes from a variety of sources, especially old IBM documents on, as well as information from the IBM 1401 restoration team, especially Tim Coslet's SMS data and Jim Hunt's data. Much of this information was obtained through OCR, so don't expect complete accuracy. These pages are not associated with IBM in any way.