A bench technician uses a 100\text{ k}\Omega linear potentiometer as an adjustable control… — Armed Services Vocational Aptitude Battery (ASVAB)

A bench technician uses a $100\text{ k}\Omega$ linear potentiometer as an adjustable control element in a circuit. If the wiper is adjusted to $75\%$ of its full mechanical travel away from the lower reference terminal, what is the resulting resistance between the wiper and the upper terminal in kilo-ohms ( $\text{k}\Omega$ )?

Answer: 25 k\Omega

Answer

25 kilo-ohms (

25\text{ k}\Omega

)

In a linear-taper potentiometer, the total end-to-end resistance (

100\text{ k}\Omega

) is distributed uniformly across the resistive track between the outer fixed terminals. When the wiper is moved

75\%

of the travel distance from the lower terminal, the remaining segment between the wiper and the upper terminal comprises

25\%

(

100\% - 75\%

) of the total resistance. Multiplying

100\text{ k}\Omega \times 0.25

gives

25\text{ k}\Omega

Step-by-Step Solution

Find the percentage of the resistive element situated between the wiper contact and the upper terminal.

100\% - 75\% = 25\%

The total resistive track spans

100\%

of the component's resistance between its two outer end terminals.

Calculate the resistance across this upper portion of the track.

100\text{ k}\Omega \times 0.25 = 25\text{ k}\Omega

Because the potentiometer is linear, resistance is directly proportional to the physical position of the wiper along the track.

Key Concept

Linear potentiometer terminal division and wiper position relationships

Alternative Method

Calculate the resistance from the lower terminal to the wiper first (

100\text{ k}\Omega \times 0.75 = 75\text{ k}\Omega

), and subtract that value from the total resistance:

100\text{ k}\Omega - 75\text{ k}\Omega = 25\text{ k}\Omega

Estimated Time:45s

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Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Alternative Method

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