Which option is NOT a type of capacitor?

• A. Electrolytic
• B. Non-polarized
• C. Variable
• D. Resistor

Answer: (D)

Capacitors store energy in an electric field between plates and come in types like electrolytic, non-polarized, and variable, each designed for different applications but all fundamentally capacitance-based. Electrolytic capacitors are polarized and offer high capacitance in a small package; non-polarized capacitors can handle alternating current without a polarity concern; variable capacitors allow tuning by changing plate spacing or overlap. A resistor, by contrast, is a device that limits current and dissipates power as heat, described by Ohm’s law and a fixed resistance value. It does not store charge or energy over time in the way a capacitor does, and its impedance does not depend on frequency the way a capacitor’s does (though in real circuits you’ll often see them together in RC networks). So the option that is not a type of capacitor is the resistor.