Video Source By- Learning Engineering
Zener diode is a particular type of diode that,
unlike a normal one, allows current to flow not only from anode to
cathode, but also in the reverse direction, when the so-called
"Zener voltage" is reached. Zener diodes have a highly doped p-n junction. Normal diodes will also break down with a reverse voltage. Also normal diodes are not
designed to operate in the breakdown region, but Zener diodes can constantly
operate in this region.
Construction of Zener Diode:-
The Zener diode's operation depends on the significant doping of its p-n junction. The depletion region fashioned within the diode is extremely thin. and also the electric field is consequently terribly high even for atiny low reverse bias voltage of concerning 5 Volt, permitting electrons to tunnel from the valence band of the p-type material to the conduction band of the n-type material.
 |
| Circuit Symbol of Zener Diode |
I-V characteristics curve of Zener Diode:-
The Zener Diode is used in its “reverse bias” or reverse breakdown mode; the diodes anode connects to the negative supply. From the I-V characteristics curve, we are able to see that the zener diode includes a region in its reverse bias characteristics of just about a constant negative voltage despite the value of the current flowing through the diode, and remains nearly constant even with massive changes in current as long because the zener diodes, current remains between the breakdown current IZ(minimum) and also the most current rating IZ(maximum).
This ability to control itself is wont to great result to regulate or stabilise a voltage source against supply or load variations. the very fact that the voltage across the diode within the breakdown region is sort of constant turns out to be a crucial characteristic of the zener diode. because it is employed in the simple kinds of transformer applications.
The perform of a regulator is a relentless output voltage to a load connected in parallel with it in spite of the ripples within the supply voltage. or the variation within the load current and also the zener diode can still regulate the voltage till the diodes current falls the minimum IZ(minimum) worth within the reverse breakdown region.