Which component allows current to flow in only one direction?

Which component allows current to flow in only one direction?

• A. Diode
• B. Wires
• C. LDR
• D. Thermistor

Answer: (A)

A diode is used to make current flow in only one direction. It contains a p-n junction that forms a depletion region, which acts as a barrier to charge carriers. When the diode is forward biased (positive voltage on the anode, negative on the cathode), the barrier is reduced and charge carriers can cross, allowing current to flow. When reverse biased, the barrier widens and current is greatly blocked, so almost no current passes. Wires simply conduct in either direction, not restricting flow. An LDR changes resistance with light, and a thermistor changes resistance with temperature, but neither forces current to go one way. So the diode is the component that permits current in one direction only.

A diode is used to make current flow in only one direction. It contains a p-n junction that forms a depletion region, which acts as a barrier to charge carriers. When the diode is forward biased (positive voltage on the anode, negative on the cathode), the barrier is reduced and charge carriers can cross, allowing current to flow. When reverse biased, the barrier widens and current is greatly blocked, so almost no current passes. Wires simply conduct in either direction, not restricting flow. An LDR changes resistance with light, and a thermistor changes resistance with temperature, but neither forces current to go one way. So the diode is the component that permits current in one direction only.