SOLUTION

A diode is a two-electrode (two-terminal) device that acts as a one-way conductor. The most basic type of diode is the PN-Junction diode. When forward bias PN junction diode conducts. When reverse biased, it effectively blocks the flow of charge (current).

• A diode permits a current flow when the voltage on the anode is positive with respect to the voltage on the cathode.
• A diode inhibits current flow when the voltage on the anode is negative with respect to the voltage on the cathode.

A diode is called forward biased when the anode is positive with respect to the cathode. A forward-biased diode functions like a closed switch permitting current flow.

A diode is called reversed biased when the anode is negative with respect to the cathode. A reversed biased diode functions like an open switch (infinite Resistance) inhibiting current flow.

Based on the characteristics of a switch the following statements can be considered about the ideal diode:

When reverse biased (open switch):

• The diode has infinite resistance.
• The diode does not pass current.
• The diode drops the applied voltage across its terminals.