This set of Digital Electronics/Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Emitter-Coupled Logic(ECL)”.

1. The full form of ECL is __________
a) Emitter-collector logic
b) Emitter-complementary logic
c) Emitter-coupled logic
d) Emitter-cored logic

2. Which logic is the fastest of all the logic families?
a) TTL
b) ECL
c) HTL
d) DTL

3. The full form of CML is __________
a) Complementary mode logic
b) Current mode logic
c) Collector mode logic
d) Collector Mixed Logic

4. Sometimes ECL can also be named as __________
a) EEL
b) CEL
c) CML
d) CCL

5. In an ECL the output is taken from __________
a) Emitter
b) Base
c) Collector
d) Junction of emitter and base

6. The ECL behaves as __________
a) NOT gate
b) NOR gate
c) NAND gate
d) AND gate

7. In ECL the fanout capability is __________
a) High
b) Low
c) Zero
d) Sometimes high and sometimes low

8. ECL’s major disadvantage is that __________
a) It requires more power
b) It’s fanout capability is high
c) It creates more noise
d) It is slow

9. The full form of SCFL is __________
a) Source-collector logic
b) Source-coupled logic
c) Source-complementary logic
d) Source Cored Logic

10. The equivalent of emitter-coupled logic made out of FETs is called __________
a) CML
b) SCFL
c) FECL
d) EFCL

11. ECL was invented in _______ by __________
a) 1956, Baker clamp
b) 1976, James R. Biard
c) 1956, Hannon S. Yourke
d) 1976, Yourke

12. At the time of invention, an ECL was called as __________
a) Source-coupled logic
b) Current Mode Logic
c) Current-steering logic
d) Emitter-coupled logic

13. The ECL circuits usually operates with __________
a) Negative voltage
b) Positive voltage
c) Grounded voltage
d) High Voltage

14. Low-voltage positive emitter-coupled logic (LVPECL) is a power optimized version of __________
a) ECL
b) VECL
c) PECL
d) LECL

Answer: c
Explanation: Low voltage positive emitter coupled logic (LVPECL) is a power optimized version of PECL using a +3.3 V instead of 5 V supply.

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