NCEES FE Electrical and Computer Practice Exam 2025 – All-in-One Guide to Master Your Engineering Fundamentals!

The key distinction between synchronous and asynchronous counters lies in the triggering of the flip-flops used in their design. In synchronous counters, all flip-flops are triggered simultaneously by a common clock signal. This means that every flip-flop changes its state at the same moment, allowing for precise control and consistent timing throughout the entire circuit. The synchronous nature minimizes the propagation delay that can occur in designs where flip-flops are triggered at different times.

On the other hand, asynchronous counters, also known as ripple counters, trigger their flip-flops in sequence. The output of one flip-flop triggers the next, which can lead to increased delay as the change in state ripples through the circuit. This can impact the overall speed and reliability of the counter, particularly at higher frequencies or in more complex circuits.

Other options present valid points but do not encapsulate the foundational difference like the characteristic of simultaneous triggering in synchronous counters. While speed and reliability may indeed vary between these two types of counters, the simultaneous triggering of all flip-flops in synchronous design is what fundamentally distinguishes it.