Measurement reference — definition of ground: In practical electronic circuits, “ground” (or reference) is the node against which all other voltages are measured. Decide whether this statement accurately describes ground.
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ACorrect
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BIncorrect
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CTrue only for earth-grounded systems
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DTrue only in AC power circuits
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EValid only when the chassis is metal
Answer
Correct Answer: Correct
Explanation
Introduction / Context:Voltage is inherently a difference in electric potential between two points. To report a single number for “the voltage” at a node, engineers choose a reference node—commonly called ground (GND). Understanding that ground is a reference, not always literally the Earth, is essential for measurement, safety, and PCB design.
Given Data / Assumptions:
- Ground refers to the designated reference node in the circuit schematic.
- Measuring instruments report V_node = V(node) - V(ground).
- Earth bonding may or may not be used depending on system class.
Concept / Approach:Ground provides a common return path and a reference potential for signals and supplies. In many systems there are multiple grounds (analog, digital, chassis) that are tied at a single point. Whether connected to Earth or not, the chosen ground serves as the zero-volt reference for measurements and specifications throughout the circuit.
Step-by-Step Solution:
Identify the reference node on the schematic (usually the ground symbol).Understand that meter black lead connects to ground to measure node voltages.Recognize that absolute potential is not required; only differences matter.Conclude that defining ground as the measurement reference is accurate.Verification / Alternative check:Oscilloscope probes and DMMs default to ground-referenced measurements; datasheets specify output “with respect to GND,” confirming the definition in practice.
Why Other Options Are Wrong:
- Incorrect: Ground is indeed the reference node by definition.
- True only for earth-grounded systems / AC power circuits / metal chassis: Ground as a reference applies irrespective of earthing method or enclosure material.
Common Pitfalls:Assuming ground always equals Earth potential; mixing up safety ground, chassis ground, and signal return; creating ground loops by multiple bonding points.
Final Answer:Correct