Chapter 27, Problem 7P

You are working at an electronics fabrication shop. Your current project is on the team producing resistors for the timer circuit that delays the closing of an elevator door. According to its design specification, the timer circuit is to have a resistance of 32.0 Ω between two points A and B. As your resistors come off the assembly line, you find that they have a variation of ±5.00% from this value. After a team meeting to evaluate this situation, the team decides that resistances in the range 32.0 ± 0.5 Ω are acceptable and do not need modification. For resistances outside this range, the director does not wish to discard the resistors, but rather to add extra resistors in series or parallel with the main resistor to bring the total equivalent resistance to the exact design value of 32.0 Ω. You are put in charge of procuring the extra resistors. What range of resistances for these extra resistors do you need to cover the entire range of variation of ±5.00%? All resistances can be measured to three significant figures.