3. A tunnel diode or Esaki diode is a type
of semiconductor that is capable of very fast
operation, well into the microwave frequency
region, made possible by the use of
the quantum mechanical effect
called tunneling. The tunnel diode s basically a
pn junction with heavy doping of p type and n
type semiconductor materials
It was invented in August 1958 by Leo
Esaki when he was with Tokyo Tsushin Kogyo,
now known as Sony. In 1973 he received the
Nobel Prize in Physics,
Introduction
4. Tunnel diode is the p-n junction
device that exhibits negative
resistance. That means when the
voltage is increased the current
through it decreases.
Definition
5. Circuit symbol
The tunnel diode is a two
terminal device with p type
semiconductor acting as
anode and n type
semiconductor as cathode.
The circuit symbol of tunnel
diode is shown
8. Advantages of tunnel diode
1. High speed of operation due to the fact
that the tunneling takes place at the speed
of light.
2. Low cost
3. Low noise
4. Environmental immunity
5. Low power dissipation
6. Simplicity in fabrication
7. Longevity
9. Disadvantages of tunnel diode
1. Low output voltage swing
2. Because it is a two terminal device, there is
no isolation between input and output.
Applications of tunnel diode
1. Tunnel diodes are used as very high
speed switches
2. Used as high frequency micro wave
oscillator
