Digital test equipment – is a logic pulser used to detect floating logic levels on a node?

Difficulty: Easy

Correct Answer: Incorrect

Explanation:


Introduction / Context:
A logic pulser and a logic probe are complementary handheld tools used in digital electronics labs and troubleshooting. This question checks whether you understand what each tool actually does: injecting pulses versus sensing logic states and floating nodes.


Given Data / Assumptions:

  • A 'logic pulser' can drive a digital node with a short HIGH/LOW pulse sequence.
  • A 'floating' node means it is not driven to a valid logic 0 or logic 1, so its level is indeterminate and noise-susceptible.
  • We are discussing standard TTL/CMOS logic circuits on a bench or in-system.


Concept / Approach:
A logic pulser is a stimulator. It forces transitions on a node to see if downstream logic responds. A logic probe is a sensor. It reads whether a node is LOW, HIGH, toggling, or floating/undefined (some probes include a Hi-Z or pulse detect indicator). Therefore, using a pulser to determine floating level conflates roles; probing determines state, pulsing provides stimulus.


Step-by-Step Solution:

1) Identify the claim: “Logic pulser is used to determine floating level.”2) Recall roles: pulser = injects pulses; probe = measures logic state (including float indicators on some probes).3) Because measuring float requires a sensing function, a pulser is not the correct instrument.4) Conclusion: the statement is incorrect.


Verification / Alternative check:
Many tool kits are sold as “logic pulser + logic probe”. Manuals describe the pulser’s drive capability (for example, sourcing a brief 1 pulse) versus the probe’s threshold-based detection (LEDs for LOW/HIGH, pulse detect, sometimes Hi-Z). The division of labor confirms the conclusion.


Why Other Options Are Wrong:
“Correct” is wrong because a pulser injects transitions, it does not read a floating state. “Depends on the clock frequency” is irrelevant; floating detection is not about clock speed. “Not enough information” is unnecessary; the tool roles are standard. “Only for analog circuits” is off-topic; these tools target digital logic.


Common Pitfalls:
Confusing names: both start with “logic”, but probe senses; pulser stimulates. Another pitfall is assuming any tool connected to a node can infer float; without threshold sensing, you cannot classify a node's logic state reliably.


Final Answer:
Incorrect

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