🔍 Key Concepts

• Look closely at the internal blocks shown in figure B: rectifier, detector, amplifier, and the use of a current transformer (CT) feeding the relay. • Think about which overload relay types (thermal bimetallic, thermal solder‑pot, electromagnetic, electronic) use mechanical heating elements versus electrical/electronic signal processing. • Recall that thermal overloads are usually shown with heaters, bimetal strips, or solder pots, while electromagnetic/electronic types are often associated with CT inputs and signal conditioning blocks.

💭 Think About

• Does the diagram in figure B show any heater coils, bimetal strips, or solder pots, or does it show signal-processing blocks like filters and amplifiers? • Which of the four answer choices would most likely need a rectifier and amplifier as part of its operation? • If a CT is feeding the relay, is the relay probably acting on heat developed in an element, or on a processed electrical signal proportional to current?

✅ Before You Answer

• Verify whether the figure shows mechanical thermal elements (heaters, bimetal, solder) – if not, you can likely rule out the purely thermal types. • Confirm that the presence of a CT, rectifier, detector, and amplifier indicates a design that processes an electrical signal rather than relying on direct heating. • Before choosing, match each option with how it is typically constructed and see which one best fits a block diagram with electronic blocks instead of mechanical/thermal elements.