🔍 Key Concepts

• Grounded vs. ungrounded test equipment when working on power supplies • The role of a line isolation transformer in protecting equipment and the technician • What kinds of test setups can damage a non‑isolated switching power supply

💭 Think About

• Ask yourself what could happen if the negative lead of your scope or meter is tied to ground and you clip it to a point that is not at ground potential in a non‑isolated supply. • Consider why isolation from the AC mains is a big concern specifically for switching power supplies compared to simple linear supplies. • Think about which choice describes a real electrical hazard or risk of destroying components, versus answers that are about convenience or are clearly false.

✅ Before You Answer

• Identify which choice mentions line isolation transformer and grounded test equipment and think carefully about that situation. • Eliminate any option that claims something is "not possible" if you know in practice it can happen under some conditions. • Ask which option deals with safety and preventing damage rather than just ease of measurement or routine steps.