Ham Radio General Class Practice Test

Which of the following is an advantage of a switch-mode power supply compared to a linear power supply?

1. Faster switching time makes higher output voltage possible

2. Fewer circuit components are required

3. High frequency operation allows the use of smaller components

4. All of these choices are correct

The correct answer is: High frequency operation allows the use of smaller components

The advantage of a switch-mode power supply lies primarily in its ability to operate at high frequencies, which allows it to use smaller components. This high-frequency operation is a significant factor because it reduces the size of components such as transformers and capacitors, making the entire power supply more compact and lightweight. In contrast to linear power supplies, which operate at the mains frequency and require larger components to handle the energy transfer at that frequency, switch-mode power supplies can achieve the same power levels while employing smaller components. This characteristic is particularly beneficial in applications where space and weight are critical factors, such as in portable equipment or densely packed electronic devices. The other statements, while they may contain some truths, do not encapsulate the advantage as directly as the high-frequency operation does. For example, while fewer components can sometimes be a characteristic of switch-mode designs, the real hallmark of their efficiency and compact nature is the high frequency of operation. Thus, focusing on the smaller component usage due to high-frequency operation captures the essence of the advantage offered by switch-mode power supplies.