2. THE TUNNEL DİODE
The tunnel diode is a form of very fast semiconductor
diode that can operate well into the microwave radio
frequency region. The tunnel diode’s other name is Esaki
Diode.
TUNNEL DIODES: CIRCUIT SYMBOL:
3. Advantages and Disadvantages
of Tunnel Diodes
Advantages:
Very high speed
Longevity
Disadvantages:
Reproducibility
Low peak to valley current ratio
4. Tunnel Diode Theory Basics
The characteristic curve for a tunnel diode shows an
area of negative resistance.
Tunnel diode I-V characteristic
5. Normal diode current
Tunneling current
Excess current
Tunnel Diode Characteristic
6. Tunnel Diode Structure Basics
A further difference is that the depletion region, the area
between the p-type and n-type areas, where there are no
carriers is very narrow.
7. Backward Diode Basics
In the forward direction the tunnelling effect is much
reduced and it follows virtually the same characteristic
as a normal PN junction diode.
8. Backward Basics
A backward diode is a form of tunnel diode where one
side of the junction is less heavily doped than the other.
The fact that the diode can be used 'backward' way
round gives rise to its name.
9. Breakdown diode circuit
symbol
Despite the operation of the breakdown diode, its
circuit symbol is based on that for the standard diode,
but has 'tails' added to the bar element visible either
side of the bar to indicate its operation and to
differentiate it from other forms of PN junction diode.
10. Backward diode applications
The characteristics of the backward diode make it
suitable for a limited number of applications where
other diodes may not perform as well.
1. Detector
2. Rectifier
3. Switch
11. Backward Diode Tutorial
The backward diode uses much the same structure as
the tunnel diode, but it has a different IV characteristic
making it useful in a variety of applications.
12. Basics
A backward diode is a form of tunnel diode where one
side of the junction is less heavily doped than the other.
