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1answer
33 views

Why is the voltage across a PN junction 0 v when it is in open circuit conditions? [duplicate]

Why is the voltage across a PN junction 0 v when it is in open circuit conditions ?
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1answer
56 views

Cutoff and Conducting diodes

Why is D1 considered cutoff and D2 considered conducting ? Note : I am working with constant voltage model where the diode voltage is 0.7v and I need to figure out I and V. Please explain why D1 is ...
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1answer
91 views

Why can current flow through the reverse biased base-collector junction (N-P junction) in a BJT with a forward biased base-emitter junction?

If the base-emitter junction of a BJT is forward biased, then current can flow through the reverse biased base-collector junction (N-P junction). This disagrees with my understanding of the PN ...
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2answers
392 views

minority carrier life time? Why is it important for devices' switching speed. Why not majority carriers?

I am trying to get my head around why would and silicon engineer care about the minority life time carrier and how does the minority carrier affect the switching speed of PN junction. Why is it so ...
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3answers
199 views

Understanding the PN-Junction Built in Voltage

I don't like asking duplicate questions but I couldn't find one that was quite the same. I apologize if it is similar to another. TL;DR: How can a charge neutral substance have a potential? Why ...
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0answers
54 views

Grading/Doping of pn junctions

I was studying about pn junction grading and junction capacitance and I came to look at step graded and linear graded junctions. I read that step grading in done for the base emitter junctions of a ...
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3answers
65 views

Transportation of holes

I was studying pn junctions and came across the concepts of diffusion currents. From what I understand is, when the junctions come together, since there is an excess of donors on the n side and an ...
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3answers
1k views

Why isn't there a potential difference across a disconnected diode?

I know this question sounds silly, as if there was a potential difference a current would be created when the terminals are connected together and this would mean energy has come from somewhere. The ...
1
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1answer
112 views

Does a reverse-biased P-N junction create quantum noise?

It is my understanding that a highly doped, thin depletion region, reverse-biased P-N junction at low voltage can cause quantum mechanical tunneling. This (or sometimes avalanche breakdown) is used ...
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0answers
38 views

What happens to the energy bands when a forward bias > Buit-in potential is applied [duplicate]

When we applied a forward bias across a PN junction, the barrier height of the depletion region reduces. What will happen to the energy bands when we apply the forward bias greater that the built-in ...
0
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1answer
61 views

How is the PN junction formed?

I am confused about a couple of points: When the electrons diffuse from N side to P side, and holes diffuse from P side to N side, negative charged region is formed at the junction in P type and ...
4
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7answers
353 views

Resistance of a semiconductor diode

When we calculate the dynamic resistance \$r=(\frac{dv}{dI})\$, for any n-p junction, how is it different from the normal resistance \$R=\frac VI\$? Does the equation for the voltage drop (The fermi ...
3
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1answer
98 views

Is my avalanche noise “random?”

I'm working on a hardware random number generator based on the below design. It uses two reverse P-N junctions to create avalanche noise. I was looking at the circuit with my oscilloscope, and I ...
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0answers
80 views

Equivalent circuit for solar cell

I have a question regarding the equivalent circuit for a solar cell. The circuit includes a diode to model the p-n junction of the cell. When some part of the photo-generated current flows through ...
0
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1answer
215 views

Do we include the voltage drop across a diode when calculating the current through the diode, taking into account breakdown has occured?

So, am doing this question paper for my electronics, and I stumble across a question that asks me to calculate the current through a diode, with a breakdown voltage of 1.7, an Imax current of 20ma, ...
2
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1answer
208 views

Potential drops in BJT in CE configuration?

In a simple p-n junction diode, there is a \$V_{eq}\$, the potential difference between the p-doped and the n-doped portion of the diode. When an external potential \$V\$ is applied in forward bias, ...
0
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1answer
78 views

Reverse voltage PN junction (how it works?)

I have this block inside my circuit, which is supposed to drawn a current from the main line to the GND whenever there is this signal in the transistor base (simple diagram): The main line can ...
4
votes
1answer
6k views

Why MOSFET Pinchoff occurs

This question is regard to enhanced n-type MOSFETs. From what I understand, an inversion layer is formed underneath the insulating layer below the gate of the MOSFET when a voltage is applied to the ...
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2answers
356 views

Diode PN Junction Understanding

I have a question about how the PN junction works in a diode. According to http://hyperphysics.phy-astr.gsu.edu/hbase/solids/pnjun.html: "Filling a hole makes a negative ion and leaves behind a ...
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2answers
276 views

What happens when a AC current is applied to a PN junction? [closed]

What would happen if a AC current is applied to a PN junction? Is the input current a sine wave?
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1answer
867 views

Depletion Region of a FET

So I finally Dived into understanding the P-N Junction and Field Effect Transistors. (this may almost be teetering on the "Physics portion" of electronics, but it's still mainly for understanding the ...
2
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3answers
564 views

Understanding reverse biased PN junction

I'm trying to understand a reverse biased PN junction, conceptually. For reference, I'll adopt the convention that the P-type is on the left, and N-type is on the right. So without a bias, the ...
2
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0answers
269 views

Industrial construction of pn-junction diodes?

I was just doing a project for a website and my team member excavated a standard pn-junction diode to see that inside the ceramic casing, the semiconductors of p and n doping merely abut together in ...
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3answers
2k views

Simple pn junction / diode question

Lest assume we have the setup presented in the image. What would be the potential difference (not voltage drop) between points A and B? Why? What effect will the pn junction barrier potential have ...
1
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1answer
331 views

Excess minority carrier concentrations at the edges of the depletion layer

In a pn juction how do the excess minority carrier concentrations at the edges of the depletion layer p'(xn ),n'(−xp ) depend on the forward-bias voltage? Are these the maximum concentrations of the ...
2
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2answers
292 views

Light levels affecting IV curves for a Diode

I conducted an experiment to work out the saturation current under reverse bias for a diode in three different scenarios, ambient lighting, low light levels and high light levels. Is there an equation ...