Zener Diode
ZENER DIODE
Zener diode is a pn junction diode, designed to operate inwards contrary breakdown region. Actually a zener diode varies from pn junction diode exclusively due to the doping level. In a zener diode the doping marking is really high when compared to the pn junction diode. And also the zener diode is used every bit a voltage regulator inwards contrary bias condition. The contrary breakdown voltage of a zener diode depends on the doping level. So doping marking matters inwards zener diode.
VI CHARACTERISTICS OF PN JUNCTION VS ZENER DIODE:
WORKING:
Generally a zener diode plant inwards iii operating regions or stages, they are,
- FORWARD REGION
- LEAKAGE REGION
- BREAKDOWN REGION
We are going to run across individually close these regions inwards the upcoming paragraphs!
1. FORWARD REGION:
- FORWARD REGION
- LEAKAGE REGION
- BREAKDOWN REGION
During the frontwards bias status (ie)when the positive concluding of the battery is connected to the anode in addition to the negative concluding of the battery is connected to the cathode of the zener diode, the diode volition non send until it cross overs the barrier voltage which is to a greater extent than or less equal to 0.7 for sillicon in addition to 0.3v for germanium type material. The barrier voltage is created due to the fact that since the diode consist of a p type in addition to a n type material, the holes from the p type percentage combine amongst the electrons of the n type percentage at the junction layer which causes a layer of immobile ions which acts every bit a barrier to the catamenia of the current. Hence this barrier layer is called depletion layer in addition to the voltage which takes to completely demolish this depletion layer is called barrier voltage. When the given voltage is equal in addition to greater than the barrier voltage the depletion layer disappears in addition to the conduction starts. This procedure of zener diode is same every bit the pn junction diode.
2.LEAKAGE REGION:
During the contrary bias status where the positive concluding of the battery is connected to the anode halt in addition to the positive concluding of the battery is connected to the cathode end, the depletion layer volition perish much greater in addition to no electrical current volition catamenia according to the theory. But genuinely a practical electrical current flows during contrary bias during the increment inwards contrary bias voltage which is denoted every bit the contrary saturation current. This pocket-size contrary electrical current which flows nether contrary bias status is called contrary saturation electrical current inwards other words. The percentage is called every bit leakage region.
3.BREAKDOWN REGION:
As nosotros perish along on increasing the contrary bias voltage other than normal the zener diode shows a weird phenomenon of maintaining voltage. Actually due to the high doping nature of the zener diode the heighten of voltage to its peak causes interatomic bonds to intermission causing a set out of ions resulting inwards catamenia of electrical current piece the voltage remains the same. The breakdown voltage of the zener diode totally depends on the doping level. There are 2 types of breakdown,
As the contrary bias voltage gets increases the thermally generated carrier ions due to he higher contrary bias voltage, larn to a greater extent than kinetic loose energy than the normal ions fron the contrary bias voltage every bit a result, the velocity of the carrier ion increases.
These electrons disturb the covalent bond past times colliding amongst the immobile ions in addition to practice novel electron hole pairs. These novel accuse carriers larn sufficient loose energy from the electrical champaign in addition to collide amongst other immobile ions making them mobile. Thereby generating farther electrons holes pairs. This procedure is stimulative in addition to generates an avalanche of accuse carriers inwards a brusk time. This procedure is called every bit avalanche breakdown.
ZENER BREAKDOWN:
During the contrary bias status when nosotros perish along on increasing the contrary bias voltage the rupture of covalent bonds receive got house at the potent electrical champaign at the junction. New electron hole pairs are released amongst increases the contrary current. For lightly doped diode nosotros receive got exclusively avalanche breakdown.
ZENER DIODE AS Influenza A virus subtype H5N1 VOLTAGE REGULATOR:-
{SHUNT REGULATOR}
Consider the to a higher house circuit diagram for meliorate understanding.
Actually it consist of 2 resistances 1 is the input resistance ri in addition to the other is the output resistance rl or it is also called every bit charge resistance. The zener diode is connected inwards parallel amongst the input beginning in addition to the charge voltage where you lot tin dismiss attach the voltmeter in addition to mensurate the readings. As the diode is inwards parallel amongst the charge the regulator or the diode is called every bit shunt regulator.
Iin=Iz +Io
Iin=(Vin -Vz)/Rin
Since for the zener diode the output voltage equals the output of the zener diode, Vo=Vz;
THEREFORE
Io=Vo/Rl
Though the output voltage varies amongst these 2 reasons every bit good which include,
CHANGE IN INPUT VOLTAGE:
Let us assume the charge resistor is fized in addition to the input voltage tin dismiss hold out varied. Even that illustration the output voltage is equal to the output of the zener diode.
case1.
If Vin increases in addition to so the input electrical current I inwards increases it is constant because Vo=Vz in addition to rl is fixed thence from kcl equation every bit Iin increases. nthe corresponding direct chances volition reverberate inwards Iz.
illustration 2.
If Vin increases Iin decreases because of which Iz. decreases. Vo volition all fourth dimension never genuinely a server. But the Vo remains constantly forcefulness him to the proficient certificate.
APPLICATION:
2.LEAKAGE REGION:
During the contrary bias status where the positive concluding of the battery is connected to the anode halt in addition to the positive concluding of the battery is connected to the cathode end, the depletion layer volition perish much greater in addition to no electrical current volition catamenia according to the theory. But genuinely a practical electrical current flows during contrary bias during the increment inwards contrary bias voltage which is denoted every bit the contrary saturation current. This pocket-size contrary electrical current which flows nether contrary bias status is called contrary saturation electrical current inwards other words. The percentage is called every bit leakage region.
3.BREAKDOWN REGION:
As nosotros perish along on increasing the contrary bias voltage other than normal the zener diode shows a weird phenomenon of maintaining voltage. Actually due to the high doping nature of the zener diode the heighten of voltage to its peak causes interatomic bonds to intermission causing a set out of ions resulting inwards catamenia of electrical current piece the voltage remains the same. The breakdown voltage of the zener diode totally depends on the doping level. There are 2 types of breakdown,
AVALANCHE BREAKDOWN:
- AVALANCHE BREAKDOWN
- ZENER BREAKDOWN
As the contrary bias voltage gets increases the thermally generated carrier ions due to he higher contrary bias voltage, larn to a greater extent than kinetic loose energy than the normal ions fron the contrary bias voltage every bit a result, the velocity of the carrier ion increases.
These electrons disturb the covalent bond past times colliding amongst the immobile ions in addition to practice novel electron hole pairs. These novel accuse carriers larn sufficient loose energy from the electrical champaign in addition to collide amongst other immobile ions making them mobile. Thereby generating farther electrons holes pairs. This procedure is stimulative in addition to generates an avalanche of accuse carriers inwards a brusk time. This procedure is called every bit avalanche breakdown.
ZENER BREAKDOWN:
During the contrary bias status when nosotros perish along on increasing the contrary bias voltage the rupture of covalent bonds receive got house at the potent electrical champaign at the junction. New electron hole pairs are released amongst increases the contrary current. For lightly doped diode nosotros receive got exclusively avalanche breakdown.
ZENER DIODE AS Influenza A virus subtype H5N1 VOLTAGE REGULATOR:-
{SHUNT REGULATOR}
Consider the to a higher house circuit diagram for meliorate understanding.
Actually it consist of 2 resistances 1 is the input resistance ri in addition to the other is the output resistance rl or it is also called every bit charge resistance. The zener diode is connected inwards parallel amongst the input beginning in addition to the charge voltage where you lot tin dismiss attach the voltmeter in addition to mensurate the readings. As the diode is inwards parallel amongst the charge the regulator or the diode is called every bit shunt regulator.
Iin=Iz +Io
Iin=(Vin -Vz)/Rin
Since for the zener diode the output voltage equals the output of the zener diode, Vo=Vz;
THEREFORE
Io=Vo/Rl
Though the output voltage varies amongst these 2 reasons every bit good which include,
- change inwards input voltage:
- change inwards charge current:
CHANGE IN INPUT VOLTAGE:
Let us assume the charge resistor is fized in addition to the input voltage tin dismiss hold out varied. Even that illustration the output voltage is equal to the output of the zener diode.
case1.
If Vin increases in addition to so the input electrical current I inwards increases it is constant because Vo=Vz in addition to rl is fixed thence from kcl equation every bit Iin increases. nthe corresponding direct chances volition reverberate inwards Iz.
illustration 2.
If Vin increases Iin decreases because of which Iz. decreases. Vo volition all fourth dimension never genuinely a server. But the Vo remains constantly forcefulness him to the proficient certificate.
APPLICATION:
- THE ZENER DIODE IS USED AS Influenza A virus subtype H5N1 VOLTAGE REGULATOR AND Influenza A virus subtype H5N1 RECTIFIER TOO.
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