Which component permits current to flow in only one direction?

Which component permits current to flow in only one direction?

• A. Direct Current
• B. Ground
• C. Diode
• D. Electromagnet

Answer: (C)

The unidirectional flow is provided by the diode. A diode has a PN junction that conducts easily when the anode is more positive than the cathode (forward bias), allowing current to pass. When the polarity is reversed (reverse bias), the depletion region widens and blocks current, so almost no current flows in that direction. This makes the diode a one-way current path, which is precisely why it’s used in rectifiers and to protect circuits from reverse polarity. The other options don’t inherently enforce direction. A direct current is a type of current, not a component that controls flow; ground is a reference/return path, not a device to pass current in only one way; an electromagnet is a coil that creates a magnetic field when current passes but doesn’t inherently restrict current to a single direction.

The unidirectional flow is provided by the diode. A diode has a PN junction that conducts easily when the anode is more positive than the cathode (forward bias), allowing current to pass. When the polarity is reversed (reverse bias), the depletion region widens and blocks current, so almost no current flows in that direction. This makes the diode a one-way current path, which is precisely why it’s used in rectifiers and to protect circuits from reverse polarity.

The other options don’t inherently enforce direction. A direct current is a type of current, not a component that controls flow; ground is a reference/return path, not a device to pass current in only one way; an electromagnet is a coil that creates a magnetic field when current passes but doesn’t inherently restrict current to a single direction.