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Difficulty: MediumResistors and Potentiometers

An electronics technician connects a circuit using only the two outer stationary terminals of a 10 kΩ10\text{ k}\Omega potentiometer, leaving the center wiper terminal unconnected. How will the resistance between the two connected terminals behave as the adjustment shaft is rotated?

  1. It remains constant at 10 kΩ10\text{ k}\Omega regardless of shaft rotation.Answer
  2. B
    It varies smoothly from 0 Ω0\ \Omega to 10 kΩ10\text{ k}\Omega as the shaft turns.
  3. C
    It acts as an open circuit with infinite resistance because the wiper is disconnected.
  4. D
    It remains fixed at 5 kΩ5\text{ k}\Omega across the circuit.

Answer

The resistance remains constant at 10 kΩ10\text{ k}\Omega regardless of shaft rotation.
A standard potentiometer has a continuous resistive element with fixed end contacts. Connecting exclusively to the two outer terminals places the entire 10 kΩ10\text{ k}\Omega track in series with the circuit. Because the movable wiper is not part of the active electrical path, rotating the control shaft has no effect on the total resistance between the outer terminals.

Step-by-Step Solution

1
Identify the internal construction of a standard three-terminal potentiometer.
A potentiometer consists of a continuous resistive track of fixed total resistance (10 kΩ10\text{ k}\Omega) connected between its two outer stationary terminals, along with an adjustable center wiper that slides along that track.
Understanding the physical arrangement determines which paths conduct current.
2
Analyze the circuit path when only the two outer terminals are connected.
Current flows through the entire continuous length of the resistive strip from one end to the other without passing through the wiper.
Since the center wiper terminal is unconnected, its mechanical movement along the track cannot alter the total length or resistance between the two fixed outer end points.

Key Concept

Potentiometer terminal anatomy and resistive track behavior
Estimated Time:40s
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Topics

Resistors and Potentiometers

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