In variable resistors (potentiometers used as controls), if the resistance does not change uniformly with shaft rotation, how is the device classified?

Introduction / Context:
Rotary variable resistors are specified by how resistance changes versus shaft angle. Two common laws are linear (uniform change) and tapered (nonuniform change, such as logarithmic or audio taper). Recognizing these behaviors is essential when selecting controls for volume, brightness, and sensor interfaces.

Given Data / Assumptions:

• Shaft rotation is the input variable.
• Observed resistance change with rotation is nonuniform.
• Device is a variable resistor/potentiometer used as a user control.

Concept / Approach:
A linear pot produces a resistance proportional to angle (straight-line R vs. theta). A tapered pot intentionally produces a curved response, commonly logarithmic (audio taper) or antilog (reverse audio), to match human perception or circuit requirements. Nonuniform change directly implies a taper, not a defect, provided the response matches the specified law.

Step-by-Step Solution:
Identify the R vs. angle behavior from measurement or datasheet.If R increases linearly with angle → linear law.If R increases slowly at first and then faster (or vice versa) → tapered law (log/antilog).Nonuniform change therefore classifies the device as tapered.

Verification / Alternative check:
Plot resistance at equal angle increments. A straight line indicates linear; a curve indicates taper. Datasheets label these as “A” or “B” laws depending on region/manufacturer conventions.

Why Other Options Are Wrong:

• Linear: Contradicts the observed nonuniformity.
• Defective: Nonuniformity alone does not indicate failure if the part is specified as tapered.
• Not wirewound: Wirewound construction does not determine response law; both linear and tapered versions exist.

Common Pitfalls:

• Assuming all pots are linear; many control applications require taper to suit human perception.
• Misinterpreting logarithmic behavior as a fault during quick bench tests.

Final Answer:
tapered