Assuming a 120 VAC input across TP1 and TP2...

Question 1 of 2707066636eed28f7522a1c51d34e

Assuming a 120 VAC input across TP1 and TP2 and a regulated output of 24 VDC across TP5 and ground, in which section of the 24 VDC power supply circuit illustrated does the greatest absolute change in voltage level take place? Illustration EL-0085

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Question 1 of 27070

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🔍 Key Concepts

• Typical functions of each stage in a linear DC power supply: transformer, rectifier, filter, and regulator • Where the main voltage step from 120 VAC down to a level suitable for 24 VDC usually occurs • How much voltage change is caused by a transformer turns ratio versus the smaller drops across diodes, filters, and regulators

💭 Think About

• Look at what is connected directly to TP1 and TP2 and ask: does this stage mainly change voltage level or just change waveform shape/ripple? • Compare the approximate voltage at the secondary of T1 with the regulated 24 VDC output: which block boundary contains that big reduction? • For blocks B, C, and D, think: are these stages mainly rectifying, smoothing, or fine-tuning the voltage, and how large is the typical voltage drop of each?

✅ Before You Answer

• Identify which labeled section contains the transformer T1 between primary and secondary windings • Estimate which section is responsible for the largest RMS voltage difference between its input and output, not just removing ripple • Confirm that drops across diodes, filters, and the series pass transistor are relatively small compared to the primary step from 120 VAC to a low AC voltage feeding the rectifier