Tunnel diode – semiconductor diode characterised by a small thickness of the pn junction, a very high concentration of dopants on either side and a adverse dynamic resistance for a sure range of polarizing voltages. Also because of the heavy doping, a tunnel diode displays an unusual current-voltage attribute curve as in contrast with that of an ordinary junction diode. If a small number of impurities are added to the p-n junction diode (p-kind and n-sort semiconductor), a wide depletion area is shaped. These oscillators are useful in software that requires a few millwatts of power, example- local oscillators for microwave tremendous electrodyne receiver.
Tunnel diodes should not currently widely used, as there are different alternate options available. Of course if a curve tracer is accessible, it is great for measuring the I-V curve of the diode. Sensible tunnel diodes function at just a few milliamperes and some tenths of a volt, making them low-power devices. Immune to Nuclear Radiation: Tunnel diodes are immune to the results of magnetic fields , high temperature and radioactivity.
That is the vital property of Tunnel diode as a result of as an alternative of absorbing power, a detrimental resistance produces energy. Very high frequency applications utilizing the tunnel diode are attainable because the tunneling action happens so quickly that there isn”t a transit time effect and therefore no signal distortion. he said This produces a unfavourable resistance region within the tunnel diode i-v characteristic the place a positive change in voltage produces a damaging change in current.
The IV attribute curve, mixed with the very high velocity of the diode means that the it may be used in quite a lot of microwave RF purposes as an energetic machine. This phenomenon is named the tunneling effect and is seen mainly within the tunnel diodes. Germanium tunnel diodes are extraordinarily sensitive to overheat, especially at soldering work. In tunnel diode, the valence band and conduction band power levels in the n-kind semiconductor are lower than the valence band and conduction band power levels within the p-sort semiconductor.
The destructive resistance region is the most important and most generally used attribute of the tunnel diode. At this level, the conduction band and valence band no longer overlap and the tunnel diode operates in the same manner as a normal p-n junction diode. If the power diagram of a tunnel diode by which the ahead bias has been elevated even additional, then the energy bands now not overlap and the diode operates in the same manner as a normal pn junction.