Construction Coordinator Practice Exam

Why is measuring unregulated DC voltage on an SMPS line extender unnecessary?

1. They are cheaper to operate

2. SMPS regulates DC voltage over a wider AC voltage range

3. It provides constant voltage supply

4. Measurement equipment may not be available

The correct answer is: SMPS regulates DC voltage over a wider AC voltage range

Measuring unregulated DC voltage on a switched-mode power supply (SMPS) line extender is unnecessary primarily because SMPS regulates DC voltage over a wider AC voltage range. This inherent design feature of SMPS allows for the conversion of the input voltage to a stable output voltage, which is essential for many electronic devices that require consistent power levels regardless of fluctuations in the input power supply. The regulation provided by an SMPS means that even if the AC voltage input varies, the output DC voltage remains within a specified range. Therefore, direct measurements of the unregulated DC voltage do not provide any practical value, as the output is consistently stabilized by the SMPS itself. As a result, the focus should be on ensuring that the SMPS is functioning correctly rather than taking unnecessary measurements at a stage where the voltage is already being regulated. Understanding the typical operational characteristics of SMPS helps in recognizing that the necessity to measure unregulated DC voltage diminishes significantly when the system is designed to maintain stable output under varying conditions.