What is a diode?

What is a diode?

• A. A device that stores energy in a capacitor
• B. A device that allows current to flow through it only in one direction
• C. A device that increases resistance
• D. A device that converts mechanical energy to electrical energy

Answer: (B)

A diode acts as a one-way valve for electrical current. It’s a semiconductor device with a PN junction that conducts readily when the anode is more positive than the cathode (forward bias) and blocks current when the polarity is reversed (reverse bias). This directional behavior is why diodes are used to convert alternating current to direct current (rectification) and to protect circuits from reverse polarity. Other components do not share this one-way current property: a capacitor stores energy, a resistor primarily limits or drops voltage, and a generator converts mechanical energy into electrical energy.

A diode acts as a one-way valve for electrical current. It’s a semiconductor device with a PN junction that conducts readily when the anode is more positive than the cathode (forward bias) and blocks current when the polarity is reversed (reverse bias). This directional behavior is why diodes are used to convert alternating current to direct current (rectification) and to protect circuits from reverse polarity. Other components do not share this one-way current property: a capacitor stores energy, a resistor primarily limits or drops voltage, and a generator converts mechanical energy into electrical energy.