A diode is a two-terminal electronic component that conducts current primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance in one direction, and high (ideally infinite) resistance in the other. A diode vacuum tube or thermionic diode is a vacuum tube with two electrodes, a heated cathode and a plate, in which electrons can flow in only one direction, from cathode to plate. A semiconductor diode, the most commonly used type today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals. Semiconductor diodes were the first semiconductor electronic devices. The discovery of asymmetric electrical conduction across the contact between a crystalline mineral and a metal was made by German physicist Ferdinand Braun in 1874. Today, most diodes are made of silicon, but other semiconducting materials such as gallium arsenide and germanium are also used.
Hi everyone,
I am working with a solar cell realized with a metal-semiconductor junction. I need to find an expression for the short circuit current of this solar cell, but in the literature I have only found models for the standard case of a pn junction solar cell.
Does anyone know a...
Homework Statement
Determine Vout, the current flowing through R and power power dissipated the Zener diode.
Homework Equations
Circuit analyzing techniques.
The Attempt at a Solution
I've done this problem by assuming each diode is off while ignoring the other.
E.g...
Not really sure where this belongs... But here goes:
If you illuminate a photo diode it generates a current because electrons are being emitted from its cathode. Since each emission is however an independent stochastic process the output current will be subject to fluctuations, which can be...
Hello, I've got a problem I simply can't get my head around. Basically I need to determine the OP of the Z-Diode through graphical solution. Thus I need the graph of the Z-Diode (which we drew by hand with help of some measured values) and the graph of the equivalent circuit.
Well, I also...
I studied semiconductor basic long time ago... So I've reviewed these days.
For a while, i got a question about Schottky diode's frequency response.
That is Schottky diode has more awesome frequency response than pn diode.
Why does Schottky diode has good frequency response?
Somebody help...
I want to connect a lead-acid starting battery to a bank of deep discharge batteries on my boat via a diode. The purpose will be to let the start battery charge from the same source, but to not back feed.
First, I'm unsure how to rate the diode. 12v is maximum voltage, that's clear. But...
I have just started studying this topic and I am confused about several things.
1) Why does the assumption that D1 is reverse biased mean it is modeled as a switch? Are reverse biased diodes always modeled as a switch?
2) Also, why does the assumption that D2 is forward biased means it can...
As far as I understand, when forward biased voltage applied, electrons from N diffuse to P, then recombine. Since energy gap between conductive electron and hole is const => only certain wavelength photons is emitted.
In gaseous lasers for example you need to gain a populational inversion...
Hi, all
i am confusing about the characteristics of tunnel diode
if the dopant concentration increased, how change the turn-on voltage ?
does it depend on concentration ?
if it depends on concentration, does the turn-on voltage increase when the dopant concentration increased ?
We manufacture crank case heaters and they are designed with an 800V 1A STD Recovery diode. We do not Hi-pot the heater with the diode in it we only test to make sure we have an ohm reading in one direction and an OL in the other.
However, our customer installs our heater into a system and...
If p-type semiconductor and n-type semiconductor of a diode are equally doped, and if the diode is forward biased, then holes will move toward the n-type semiconductor and electrons will move toward the p-type semiconductor and they will diffuse with each other and the ions become neutral atoms...
Hello,
I'm an electrical engineer dipping my foot into solenoids as part of a project here at work.To monitor the position of the solenoid's armature I have a linear pot installed. My is issue revolves around a flyback diode installed across a DC solenoid I am testing. I am low side switching...
Homework Statement
First question,
In the picture attached (One diode and Resistor), when you are calculating V, is the V drop across the diode or the resistor?
Second Question,
In the second picture (circuit with current source) Why is the nodal analysis equation,
1A=V/100ohms +...
Homework Statement
A moving coil ammeter is to be adapted to detect small alternating currents. Which of the diagrams shows how a diode could be connected in order to make the conversion ?
(Options shown in attachment)
(Ans: (3))
Homework Equations
The Attempt at a Solution
I...
Homework Statement
The current-voltage characteristic curve of a semiconductor diode as a function of temperature T is given by the equation: ##I = I_0(e^{|e|\Delta V / k_BT}-1)##
where e is the base of the natural logarithm.
|e| is the charge of an electron
k_B is the boltzmann's...
Homework Statement
In a silicon junction diode, the region of the planar junction between n-type and p-type
semiconductors can be approximately represented as two adjoining slabs of charge, one
negative and one positive. Away from the junction, outside these charge layers, the
potential...
Homework Statement
Determine ##V_0## and ##I## for the network shown in attachment 1.
Homework Equations
The Attempt at a Solution
I can replace Si diode with a battery of emf of 0.7 V and Ge diode with that of 0.3 V.
If I take Path-1 (orange) in attachment 2, I get...
Hi everyone,
My subject basically revolves around diodes circuits and how to analyze them (AC, DC).
What textbook do you recommend? (If there's one with many solved problems, that would be great.)
It is well known that in order to solve diode circuits we must assume state of diodes, replace diodes with appropriate model (0.7V voltage drop) and solve circuit. Then we check result and if it agrees with initial assumption, we successfully solved our circuit.
If we mark number of diodes in...
Homework Statement
Hi so I have a problem that I don't exactly know how to approach, here's the diagram:
http://images.fr1ckfr4ck.fastmail.fm/probA.jpg
The diodes are supposed to have saturation current I_s = 10^(-15) A
Homework Equations
What is V?
The Attempt at a Solution
First I tried...
Homework Statement
Homework Equations
I=Ise(V/VT)
The Attempt at a Solution
The solution I got is wrong. Does anyone know why?
Here is my attempt, the image was too large for this forum so here is the link:
http://i.imgur.com/4tuGxdO.jpg
Homework Statement
Find V and I in the following diagram:
The Attempt at a Solution
I know what the answer is. Diode D2 is off but why?
Now if the voltage left of D2 was +4V then diode D2 is off because +4V dominates +3V so the current runs right and thus turns off D2. Is this...
I am new to mixer circuit design, but I need to build a simple mixer that will downconvert a 10 GHz signal to a DC to 3 kHz signal. I know I can do this with a schottky diode and lowpass filter to isolate the lower harmonic (f-IF = f-RF - f-LO). The problem is that the RF signal will be in the...
Homework Statement
This isn't for a homework problem per say, though it is a coursework question. I'm writing a lab report on Multi-Quantum Well Laser Diodes and am trying to explain the basic semiconductor physics behind it. As such I need a diagram of the band structure.
Homework...
I have an 800 amp car battery no load connected at anytime to a 10 watt solar panel with just a regular diode in between after 4 or 5 hours in the sun terminal voltage reads 16 volts is this good? Would a battery connected this way last longer than one that sits idle uncharged for 6 months?
John
hello guys
while studing the diode limitters
i found two examples i solved the first one but i couldn't with the second
1 -
2-
in the first i know that the diode while be forward biased in the negative half of the signal
so the negative half will be limitted to -0.7 v...
I want to know that when a pn junction diode is formed and barrier potential is setup then how can we determine the same theoretically. Also I wan to know that is there any relation between barrier potential and energy band gapSmall band gap small barrier? ?
Probably a stupid question but I'm not sure what to search for at this point.
I'm trying to do a very simple diode test (half wave rectification I suppose it's called) using an ac source. The source is a 440hz signal off of my computer soundcard (generated and played via a .wave file). It's a...
Hi, I am working on a project where I am using a LCD voltage display to measure voltage at 2 points in the circuit. The first is the voltage of the batteries providing the power, and the second is to measure the output of the circuit. It is in a very small box and I don't have room for a...
I have performed a small experiment to obtain the VI characteristics of a semiconductor diode using ANALOG DISCOVERY circuit design kit.
I have connected the arbitrary waveform generator (function generator) to a series combination of a 1N4007 diode and a 1 kilo ohm resistor.
To obtain the...
Hello guys,
I'm not getting the output of the diode logic circuits:
http://upload.wikimedia.org/wikipedia/commons/1/1f/Diode-OR2.png
If both inputs are 1, then there is current across the diodes then the output is 1, but shouldn't it drop because of the resistor R?
If both inputs are...
Homework Statement
If the circuit shown, D2= 10 times the junction area of D1. What value of V results? To obtain V=50mV, what current I2 is needed?
Homework Equations
i(D)=Is(eVD/VT-1)The Attempt at a Solution
I know junction area is related to diode current, so D2 has 10 times current as...
Homework Statement
The Attempt at a Solution
I know this might seem like a stupid question but are the 10/-20V voltage sources like the 5.3V or are they VDD (which is something different?) I'm also stuck on part a. If D2 is off, that means its not conducting, so zero current, but would there...
I am reading an old thread and because it is too old I can't post reply.
Here is the link: https://www.physicsforums.com/showthread.php?t=449044
I want to ask about the bold part. In the case, what is the voltage across the diode pair, zero or voltage source (Vin) when it is in positive half?
Homework Statement
v1 is a sine wave with amplitude ±10V and the diodes are ideal. Vo is 3V. My question is: will iB always 0?
The Attempt at a Solution
D1 will only be shorted when v1 < 0, which means that the voltage at Va would be from 0 to -10V and D2 would act as an open. Is that...
Homework Statement
Find the voltage Vo for the following circuit. Consider the diodes to be ideal.
Homework Equations
When a diode is forward biased, Diode resistance = 0Ω (Short circuited)
When a diode is reverse biased, Diode resistance is infinite (Open circuit)
Ohm's Law: V...
So in an application like this:
The coil of the motor will, by Lenz's Law, induce a very large negative voltage across its terminals. Would this voltage be very negative at the left terminal of the inductor and very positive at the right? In this way the diode will conduct, but the negative...
A typical silicon diode has potential difference of 0.7V when forward biased, to what kind of energy is the (0.7V)*(I)*(\Deltat) converted? thermal energy only? isn't there potential energy through the electric field in the pn junction?
I have read that a zener diode is just a heavily doped diode. And it conducts without burn out in its breakdown region while reverse biased at its zener voltage. But why does the zener diode sustain high reverse current just because it is heavily doped? Any help is appreciated. Thank you!
For question 1, it asks me to find the operating point by different methods.
But I have no idea to solve it. Can anyone give some hints for me?
I can just think about the diode can be replaced by an ideal diode, a 0.5V dc source and a 0.2/4=0.05Ω resistor.
For question 3,
I have solved...
The LC circuit should oscillate with its natural frequency in absence of any external agent and the energy is alternatively converted from electrical to magnetic.Suppose that i include a diode in this circuit that acts as a switch.Now the capacitor is completely discharged while diode in on...
I attached the circuit.
I need to find I_1, Voltage drop across R1, voltage drop across R2, and I_2. We're assuming the diode is 'not' ideal.
Vin=5V. R1=R2=1kohm
R3=2kohm
voltage across R2=Vin=5V
I2=5/1kohm=5mA
The real diode drops about 0.7 V. So using voltage divider gives...
I have attached the circuit of interest.
The question is to find Vd (drop across diode as shown in the attached image).
Sorry about the handwriting on there (those can be ignored).
The answer was given to be Vd=-5V.
I can't figure out how they got that answer. I don't feel there is...
A pn junction diode is driven by a voltage +E to -E volts preodically
when voltage is +E its forward biases and vice versa.
when in forward biased a current I flows through it, now if voltage is reversed to -E, current is still I (in reverse direction). This then stay constant for a time...
Dear forum,
in a diode semiconductor, the N region is rich in electrons. The P region is rich in holes.
Is the number of extra electrons in the N region equal, larger or smaller than the number of holes in the P region? If so, why?
Also, in the N region, it is said that the majority...