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A varactor diode is operated under reverse biased conditionwhy?
Wiki User
∙ 10y ago
because reverse biased current is constant upto avalanche breakdown.
Wiki User
∙ 10y ago
Wiki User
∙ 12y agocapacitive diodes run in the reverse mode
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Why should a JFET be operated with only reverse bias on the gate?
If the gate-channel junction of a JFET was not reverse biased the JFET would just act as a forward biased diode across that junction and the gate would cease to have any control over the channel conductance. For the same reason in a MOSFET the substrate-source/channel/drain junction must remain reverse biased. The MOSFET could not act as a MOSFET.
How is a non-conducting diode biased?
A nonconducting diode is biased in the reversed direction (reverse polarization).
What is best describes how a varactor diode modulator creates FM?
Resonant frequency of a circuit is proportional to sq rt (L x C). A varactor diode, when suitably voltage biased, looks like a capacitor (C). Varying the bias varies the capacitor and thus the resonant frequency .
Why fet operated in reverse bias?
you want to keep the channel electrically isolated from the gate (jfet) or substrate (mosfet) so that it operates as a fet, don't you? if it was forward biased it would just be a diode with no field effect.
Why is the input impedance of a jfet so high?
If you mean JFET, it is because the gate junction is reverse biased.
Zener diode operates In an extremely high forward bias?
False, a zener diode is normally operated reverse biased in breakdown.
When both junction of npn diode reverse biased the the diode in what state?
reverse biased
Application of varactor diode?
It includes RF design , parametric amplification ,fm, harmonic generators, voltage controlled oscillators ,in radio ,tv,cellular and wireless receivers ,and in electronic tuning .. That's it. . .
Why should a JFET be operated with only reverse bias on the gate?
If the gate-channel junction of a JFET was not reverse biased the JFET would just act as a forward biased diode across that junction and the gate would cease to have any control over the channel conductance. For the same reason in a MOSFET the substrate-source/channel/drain junction must remain reverse biased. The MOSFET could not act as a MOSFET.
How is a non-conducting diode biased?
A nonconducting diode is biased in the reversed direction (reverse polarization).
Why do we get current in reverse bias?
because semiconductor diodes are not perfect insulators when reverse biased. if you want a diode that is a perfect insulator when reverse biased, use a vacuum tube diode.
What is best describes how a varactor diode modulator creates FM?
Resonant frequency of a circuit is proportional to sq rt (L x C). A varactor diode, when suitably voltage biased, looks like a capacitor (C). Varying the bias varies the capacitor and thus the resonant frequency .
Why silicon controlled rectifier doesn't work in reverse biased condition?
Because when reverse biased it behaves like any other rectifier/diode.
Why current flow from cathode to anode in zener diode?
First off, I don't know if by current flow you mean conventional current flow or electron current flow. You realize they are in opposite directions and most electronics engineers use conventional current flow in circuit analysis.Ignoring this, I will assume your real question is "Why does current flow backwards in zener diodes compared to ordinary diodes?" The answer is that zener diodes are not operated in the forward biased range as are ordinary diodes, instead they are operated in the reverse biased range. When reverse biased enough any diode reaches breakdown voltage and suddenly conducts. Most ordinary diodes can be destroyed by breakdown, but zener diodes are designed to tolerate it. In zener diodes, this breakdown is referred to as "zener breakdown" and the voltage it happens at the "zener voltage".Low voltage zener diodes can still be used in the forward biased mode, like ordinary diodes. However most high voltage zener diodes have a "blocking diode" that is not documented on the data sheet to block forward biased operation. "Blocking diodes" are simply ordinary diodes wired in series with the zener; when the zener would be forward biased they are reverse biased (and thus blocking current), when the zener would be reverse biased they are forward biased.
Why fet operated in reverse bias?
you want to keep the channel electrically isolated from the gate (jfet) or substrate (mosfet) so that it operates as a fet, don't you? if it was forward biased it would just be a diode with no field effect.
Why collector base junction is always reverse biased for normal operation of transistors?
collector junction is reverse biased so as to remove the charge carriers away from its junction with the base.
Why is the input impedance of a jfet so high?
If you mean JFET, it is because the gate junction is reverse biased.
