A Tunnel Diode is a highly doped p–n junction diode that operates based on the principle of quantum mechanical tunneling. Due to heavy doping, the depletion region becomes extremely thin, allowing charge carriers to “tunnel” through the barrier even at low voltages.
One of its unique features is the negative resistance region in its V–I characteristics, where an increase in voltage results in a decrease in current. This property makes it useful in high-speed switching, oscillators, and microwave frequency applications.
📌 Key Point: Very fast operation due to tunneling effect, making it suitable for high-frequency electronics.
