Expanding the acronym ECL In digital electronics, what does “ECL” stand for, and how are its inputs conceptually coupled inside the gate?

Introduction / Context:
ECL is a classic high-speed bipolar logic family. Its name reflects the differential-pair topology in which inputs influence current steering via emitters rather than driving devices into saturation. Recognizing the correct expansion helps relate the acronym to the underlying circuit mechanism.

Given Data / Assumptions:

• We need both the correct expansion of “ECL” and a brief sense of how inputs are coupled.
• ECL emphasizes emitter-coupled differential pairs and constant-current sources.

Concept / Approach:
“Emitter-Coupled Logic” describes a topology where multiple input transistors share a common emitter network, steering current based on input voltages. This avoids saturation, enabling very fast transitions. Outputs are often buffered with emitter followers to drive loads with small voltage swings and low delay.

Step-by-Step Solution:

Verification / Alternative check:
Any ECL gate schematic shows input transistors with tied emitters feeding a current source and a differential load network.

Why Other Options Are Wrong:

• A/D: “Electron/energy-coupled” are incorrect expansions.
• C: While ECL often uses emitter followers at the output, saying each input transistor “functions as an emitter follower” misstates the differential input stage.

Common Pitfalls:
Confusing the emitter-follower output buffer with the emitter-coupled differential input pair.

Final Answer:
It stands for emitter-coupled logic; all of the inputs are coupled into the device through the emitters of the input transistors.