Counter taxonomy and terminology in digital electronics: Evaluate the statement: “Asynchronous counters are known as modulus counters.”

Introduction / Context:
Digital counters are categorized by timing (asynchronous/ripple vs. synchronous) and by modulus (the number of unique states before repeating). Mixing these terms leads to confusion in design discussions and troubleshooting. This item clarifies the vocabulary so learners can read datasheets and schematics accurately.

Given Data / Assumptions:

• Asynchronous (ripple) counters use the output of one flip-flop to clock the next.
• Synchronous counters clock all flip-flops simultaneously from a common clock.
• Modulus is the count length (number of distinct states) regardless of timing style.

Concept / Approach:
“Asynchronous” describes the way flip-flops are clocked, not how many states the counter has. “Modulus” describes how many unique counts occur before the sequence repeats and applies to any counter style. Therefore, calling asynchronous counters “modulus counters” is incorrect; all counters possess a modulus (e.g., mod-8, mod-10), whether asynchronous or synchronous.

Step-by-Step Solution:

Verification / Alternative check:
Inspect textbook examples: ripple mod-8 counters and synchronous mod-10 counters exist side-by-side. Both have a modulus; only one is asynchronous. Vendor counter ICs (e.g., ripple vs synchronous decade counters) prove the distinction.

Why Other Options Are Wrong:

• Correct: Mislabels a timing attribute as a modulus property.
• Only true for ring counters / Only when modulus ≥ 10 / Depends on trigger edge: These are irrelevant constraints that do not fix the misuse of terminology.

Common Pitfalls:
Assuming “decade” implies synchronous; forgetting that propagation delays accumulate in ripple counters; conflating count length with clock topology.

Final Answer:
Incorrect