All Questions
35
questions
0
votes
1
answer
61
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Clarification on Diode Recovery Times and Conduction State
I have a diode in my circuit with reverse voltage of 100 V and forward voltage of 2 V.
It experiences a reverse voltage of 100 V and immediately the voltage changes to 10 V in forward direction so it ...
1
vote
1
answer
569
views
Understanding the formula of the saturation current in a PN-junction diode
According to Wikipedia, the saturation current in a diode is given by the following formula:
$$I_S = qAn_i^2\left(\frac{1}{N_D}\sqrt{\frac{D_p}{\tau_p}} + \frac{1}{N_A}\sqrt{\frac{D_n}{\tau_n}}\right)$...
- 121
0
votes
1
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106
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Contribution of hole diffusion current and electron diffusion current in a pn junction
I have recently got to learn that the hole diffusion current and electron diffusion current both point towards the N side in a PN junction? And the diffusion current is hence towards the N side.
And ...
- 23
0
votes
1
answer
50
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Drift Current in PN Junction and Barrier Voltage
I am reading this book, but the idea presented by it is very unclear.
It quotes:
However, I am not entirely convinced with the reason it provides here, like why are the minority carriers that reach ...
- 23
3
votes
1
answer
101
views
Why is diffusion current due to p side in a diode inversely proportional to doping concentration of p side in the case of forward bias?
In a diode at equilibrium, there are Pn holes on the n side of the junction. These are maintained by the dynamic equilibrium of diffusion due to holes = drift due to holes. When a forward bias is ...
7
votes
5
answers
2k
views
Why can't a P-N junction diode be used as a voltage regulator or reference in forward bias?
Usually, a Zener or avalanche breakdown region for a suitably doped P-N junction is used for voltage regulation as a substantial variation in the current (due to minority carriers) requires a ...
- 189
0
votes
1
answer
2k
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Current density in an ideal PN junction diode
I found that the current density is as above.
The first question is: the logic is that when there is no external voltage applied, the diffusion current cancels the drift current. But there are four ...
- 101
1
vote
1
answer
110
views
Majority Charge carriers and electron holes
Suppose I have an extrinsic semiconductor made of silicon and doped with phosphorous. Now, phosphorous has one more electron than silicon. After replacing one silicon atom, and taking its place, the ...
0
votes
1
answer
208
views
Voltage fluctuation due to AC in a half wave rectifier
I think I get the broader idea of using a diode as a half wave rectifier, but I have a question:
Who provides the forward voltage or knee voltage to start the diode for rectification? I am assuming it ...
- 271
0
votes
3
answers
166
views
Do we operate diodes past their barrier or cut off voltage?
I think I get the idea of barrier or cut of voltage (e.g., 0.7 V for Si). So diodes start conducting after cut voltage. I have few questions for the cut off voltage
What happens if I increase the ...
- 271
2
votes
0
answers
57
views
How does the stored charge gets decayed when going from forward bias to zero bias?
In a pn junction diode when forward biased, excess electrons and holes get stored in p and n regions respectively.
If we short the diode by connecting p,n terminals with a wire,
how do these stored ...
- 1,150
0
votes
3
answers
1k
views
Does the current change in a Zener diode if I we increase the voltage
Zener diodes work in reverse bias in the breakdown region. At breakdown voltage, high current flows. I get till here. I want to know what happens if I increase the voltage after breakdown. Is there an ...
- 271
1
vote
2
answers
411
views
Why is the N side thinner than the P side in a photodiode?
I have been reading that a photodiode is built by sandwiching a very thin N type semiconductor togther with a thicker P type. Why is that so?
- 271
0
votes
3
answers
744
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Explanation for drift current
My question is why the concept of drift current or movement of minority charges is necessary while the pn-junction is formed. So drift current was explained to me in more or less this way
As the ...
- 23
4
votes
2
answers
1k
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Is the current in reverse biased PN junction due to drift or diffusion?
Wikipedia says
The saturation current (or scale current), more accurately the reverse saturation current, is that part of the reverse current in a semiconductor diode caused by diffusion of minority ...
- 167