Hi friends,this time we wanna discuss about zener diode which is heavily doped diode and is specially fabricated to with stand high power dissipation.
Main application of zener diode is, it can act as a voltage regulator.
Main application of zener diode is, it can act as a voltage regulator.
Forward characteristics of zener diode:
when high potential is applied at anode compared to cathode,then the characteristics of
zener diode are
Negative characteristics of zener diode:
when lower potential is applied at anode compared to cathode,then the characteristics of
zener diode are
Major concern related to zener diode is determining the state in which the zener diode is residing,there are various steps that to be followed in this process,
- Replace zener diode by an open circuit
- Find terminal voltage across the diode from N to P side,say vt
- If vt>vz, zener is reverse ON and replace it with vz
- If vt<vz, zener is OFF and hence open circuit.
now the circuit becomes
Terminal voltage Vt=(8*1.2)/(1+1.2)=4.3v and since Vt<Vz zener is OFF hence open circuit.
If RL=3.6k then terminal voltage Vt=(8*3.6)/(1+3.6)=6.26v. Here Vt>Vz hence zener is reverse ON and replace zener diode with Vz=6v.
Now the question is how to place a terminal voltage,the answer is conventional direction of zener voltage is considered to be opposite to the direction of normal PN diode,because PN diode is used in forward biased and zener diode is used in reverse biased.
For RL=3.6,the circuit becomes
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