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17
votes
3answers
959 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
vote
1answer
52 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 ...
1
vote
0answers
35 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
votes
1answer
43 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
votes
7answers
203 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 ...
2
votes
1answer
74 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 ...
1
vote
0answers
60 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
votes
1answer
105 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
votes
1answer
173 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
votes
1answer
63 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
2k 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 ...
0
votes
2answers
154 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 ...
-4
votes
2answers
208 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?
1
vote
1answer
577 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
votes
3answers
379 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
votes
0answers
253 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 ...
1
vote
3answers
1k 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
vote
1answer
218 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
votes
2answers
229 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 ...