🔍 Key Concepts
• Basic block diagram of a switched‑mode power supply (SMPS): AC line → rectifier/filter → high‑frequency chopper (inverter) → transformer → rectifier/filter → DC output
• Where regulation happens: feedback must sense the DC output and control the switching element (chopper) that sets energy into the transformer
• Difference between input‑side components (line, rectifier, input filter) and output‑side components (output rectifier, output filter, feedback from DC output)
đź’ Think About
• In a regulated switching power supply, which block must be controlled to maintain a constant DC output when input voltage or load changes? Trace where a feedback loop would logically connect.
• Look at each option and check: does the signal path start with AC mains, get rectified and filtered, then chopped at high frequency before going through the transformer, then rectified/filtered again?
• Which options show the feedback taken from the DC output and applied directly to the controller that drives the chopper (inverter), rather than feeding back to the raw AC or rectified input?
âś… Before You Answer
• Verify that the AC mains must be converted to DC first (rectifier and input filter) before feeding a high‑frequency inverter (chopper) in a typical SMPS.
• Check that the transformer is driven at high frequency by the chopper, not by 50/60 Hz mains, and that the output rectifier and filter are located after the transformer.
• Confirm that the feedback loop should sense the final DC output and return to the chopper controller / inverter drive, not back to the input rectifier or line.