Question

A dry electrolytic capacitor is made of a roll of aluminum foil coated with aluminum oxide (an insulator) on one side. The aluminum oxide acts as the dielectric and the aluminum foil is the positive capacitor plate.

A) True
B) False

Answer 1

The statement about the dry electrolytic capacitor having an aluminum foil coated with aluminum oxide acting as the dielectric is true. The oxide layer only functions correctly when the metal foil is at a higher potential than the conducting paste, and reversing the polarity can damage the capacitor.

Step-by-step explanation:

The statement that a dry electrolytic capacitor is made of a roll of aluminum foil coated with aluminum oxide on one side, where the aluminum oxide acts as the dielectric and the aluminum foil is the positive capacitor plate, is True.

In an electrolytic capacitor, the aluminum foil serves as the anode or positive plate, while the aluminum oxide layer acts as the dielectric. The electrolytic action only functions correctly when the metal foil is at a higher potential than the conducting paste. If the polarity is reversed, the oxide film can be destroyed, which is why electrolytic capacitors cannot be connected to an alternating current source.

Capacitors commonly come with a variety of dielectric materials like mica, ceramic, paper, and Teflon™ non-stick coating. These materials are critical in influencing the overall capacitance and performance of the capacitor in different applications.