Which are examples of linear components within operating limits?

• A. Resistor
• B. Capacitor
• C. Inductor
• D. Resistor, Capacitor, Inductor

Answer: (D)

The idea being tested is that linear components behave in a proportional, predictable way within specified operating limits, so their responses to inputs simply add up (superposition). Resistors follow Ohm’s law, V = IR, which is a direct, linear relationship between voltage and current. Capacitors relate current to the rate of change of voltage with i = C dv/dt, a linear dependence on how quickly the voltage changes. Inductors connect voltage to the rate of change of current via v = L di/dt, another linear relationship. When these components operate within their rated ranges, their V–I relationships stay linear, so circuit analysis using linear methods remains valid. Real devices can exhibit nonlinear behavior outside those limits (due to heating, saturation, dielectric nonlinearity, etc.), but within operating limits all three behave as linear components.