A practical application of an S–R (Set–Reset) flip-flop/latch in digital systems is as a:

Difficulty: Easy

Correct Answer: switch debouncer

Explanation:


Introduction / Context:
Mechanical switches bounce—producing multiple rapid transitions when toggled. Digital circuits can misinterpret these as multiple events. A simple memory element like an S–R latch is excellent for cleaning up such signals and delivering a stable, single transition per actuation.


Given Data / Assumptions:

  • Input is a noisy mechanical contact with bounce.
  • We need a stable digital signal at the output.
  • A minimal logic solution is preferred.


Concept / Approach:
The S–R latch stores a state: one input asserts “set,” the other asserts “reset.” By wiring a double-throw switch to generate non-overlapping set/reset assertions, the latch output changes state once per action, ignoring intermediate chatter.


Step-by-Step Solution:
Connect switch throws to generate clean S and R signals (through resistors or Schmitt triggers if desired).When the switch is pressed one way, S = 1, latch sets Q = 1.When released or toggled the other way, R = 1, latch resets Q = 0.Brief bounce pulses do not change the held state unless they assert the opposite input steadily.


Verification / Alternative check:
Oscilloscope captures of switch bounce show multiple spikes; the latch output remains stable at one level until the deliberate opposite input arrives, confirming debouncing action. Alternatively, RC + Schmitt trigger networks can be used but add analog components.


Why Other Options Are Wrong:

  • Transition pulse generator: Uses differentiators or one-shots, not an S–R latch alone.
  • Astable oscillator: Requires feedback timing network; an S–R latch by itself is not free-running.
  • Racer: Not a standard digital function.


Common Pitfalls:

  • Allowing both S and R to be asserted simultaneously; this is a forbidden condition.
  • Forgetting pull-ups/pull-downs, which can leave inputs floating and susceptible to noise.


Final Answer:
switch debouncer

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