Question 18Electricity & Electronics - QMED

The correct answer is C) opens as soon as the load current exceeds its setpoint. The key characteristic of an "instantaneous-trip" single-element type fuse is that it opens the circuit as soon as the load current exceeds its preset threshold or setpoint, without any intentional time delay. This immediate response is in contrast to other fuse types that incorporate a deliberate time delay element to allow for temporary overcurrent conditions. The instantaneous-trip design prioritizes fast protection against dangerously high currents that could potentially cause immediate damage to the electrical system. The other answer choices describe characteristics of different fuse types, such as time-delay fuses (A), circuit breakers (D), but do not accurately reflect the defining feature of an instantaneous-trip fuse.