Elevator Mechanic Practice Exam

How can you make a 300 ohm resistor if you don't have one?

1. 2 150 ohm resistors in series

2. 2 450 ohm resistors in parallel

3. 2 600 ohm resistors in parallel

4. 3 100 ohm resistors in series

The correct answer is: 2 150 ohm resistors in series

To create a 300 ohm resistor using resistors you already have, connecting two 150 ohm resistors in series is a valid method. When resistors are connected in series, their resistances add together. Therefore, combining two 150 ohm resistors yields: 150 ohms + 150 ohms = 300 ohms. This approach effectively provides the desired resistance value of 300 ohms by utilizing the series connection property of resistors. In contrast, other options do not achieve the same target resistance. For instance, resistors in parallel reduce the overall resistance, and combinations in those options would not yield a total of 300 ohms.