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.
Homework Statement
I'm trying to calculate what voltage change will compensate for a temperature change of 1 degree for a diode.
I have set up the circuit, taken down results and plotted the graph (its non-linear). So I re-plotted it using natural logs of I, and got a straight line with a...
Homework Statement
Determine reverse sat current of diode. To show and explain approach. Given-IV characteristics of diode and tabulated values for forward bias voltage from 0-0.8v and corresponding current values.
Homework Equations
At which point do I need to consider to find the...
Hi guys,
I'm trying to find a reliable formula for calculating the depletion depth in a PIN diode at a given voltage and knowing the doping of the layers. Does anyone have one? Formulae for the PN diode are common, but don't apply to the PIN directly as far as I can see.
I found a formula...
Homework Statement
Hi, I need to produce a linearized equation of the following,
I = D. V. exp(-V/B) eq(1)
I is the current
V is the voltage
D is a constant
B is a constant
Data was collected in an experiment designed to investigate the characteristics of a...
Hey all, I have a diode clamper (1 diode) and I had to use a capacitor in lab to smooth out the output (the input was a triangle wave - without the capacitor the output was still a bit triangular at the tips). This is just curiosity - can anyone explain to me how the capacitor managed to smooth...
When a DC coil (relay) is denergized, shouldn't the collapsing field cause a current that would oppose the change in current? Wouldn't that induced current be in the same direction as when the coil was enegized? Not seeing how a freewheeling doide gets forward biased. If I apply Lenz Law...
Greetings:
I recently made my first prototype surface mount board. In designing it, all the SMT components were foriegn to me. I'm a ME, not and EE and my projects are fairly straightforward microprocessor based designs. I chose components similar to old standbys I've used with through hole...
http://optics.ph.unimelb.edu.au/atomopt/publications/littrow_rsi_vol72_p4477_2001.pdf
The picture of the ECDL I explain can be found from the above web site.
The purpose of piezo is to change the cavity length of the diode laser, so that the wavelength can be varied.
From the picture...
What would happen if u had a circuit that was earthed at a point and it had an EMF of let's say 9V. If i had 1 resistor and immediately after that i had a resistor and diode in parallel, would any current enter the resistor. My understand is that it wouldn't since once the diode opens up, it...
Homework Statement
A Light emitting diode (LED) drives a single mode waveguide that is 10 km long, and has a material dispersion of – 100 ps/km/nm for wavelengths near 800 nm. The LED radiation has a spectral width of 60 nm and is centered at 800 nm.
a) If the LED is pulsed on and off in...
When drawing a circuit diagram with a forward bias dioide, is it the "fat" side of the dioide which is on the same side as the "long" side of the battery?
Thanks
Hey guys, just thought id clarify what happens when an AC current passes through a diode. Say for instance the wave featured in the link below entered a diode, what would it look like once it leaves the diode?
http://www.pcguide.com/ref/power/ext/z_ac.gif
Homework Statement
In all physics textbooks, the V-I graph for diode appears like the followings
http://211.233.39.205/phpBB2/forum_img/diode/diode-14.gif
However, when I conducted the experiment with a 1N4001 diode and 12V-AC, similar graph was found, the the graph seemed to have reflected...
Homework Statement
this is a lab task, i have found out the IV characteristic of the diode,
now they ask me to suggest a procedure to find the constant A, in the equation
I= AT^3 x exp (-E/ kT),
T being the temperature, and I = saturation current
Homework Equations
i know how to...
Homework Statement
this is a lab task, i have found out the IV characteristic of the diode,
now they ask me to suggest a procedure to find the constant A, in the equation
I= AT^3 x exp (-E/ kT),
T being the temperature, and I = saturation current
Homework Equations
i know how to...
I need to understand how diode-resistor gates work. I've read a lot about what's supposed to happen based on inputs, but I need to see some numbers & analysis to understand what's going on. Where do you start in terms of trying to analyze the following AND gate...
when forward bias of led is increased, the intensity of emitted light increases until it reaches a max after which it starts decreasing again...why?
also, in which of the two cases is barrier potential greater, led or pn diode?
Say we have a silcon pn junction (diode) - i.e., a block of p-type on
left, attached to a block of n-type semiconductor on right:
anode ------[ p | n ]------ cathode
Because of diffusion we get a barrier potention at the junction, which
makes the n-side/cathode 0.7V higher...
Homework Statement
"You are required to design a laboratory experiment to investigate how the current in a diode varies with temperature in the range of -20 to +150 Degree's C"
Homework Equations
N/A
The Attempt at a Solution
Perhaps using a freezer for the negative temp's and a...
Can someone explain me what a zener diode does? I don't know what the turn on and breakdown voltage mean, and what forward and reverse biased means.
And what the difference between a zener and a normal diode is?
Thx very much
Homework Statement
See attachment Homework Equations
We are to assume the voltage drop across diodes is .7v (don't use the diode equation!). The Attempt at a Solution
I first was assuming that both diodes were "on". Then my work is as follows:
V1 is the voltage directly above diode D1 (the...
Over size diode problem
There are two sensitive auxiliary relay in one portion of DC control circuit (relay no.1 & no.2) separated by one semiconductor diode. Two relays (R1, R2), their two run up contacts (C1, C2) and that mentioned diode bridge (D) is located in "H" form.
When relay no.1...
Homework Statement
This problem is to find the I and V by ideal diode model method (assume there is no voltage drop and resistance within the diode)
Homework Equations
Just simple Ohm's Law equation
The Attempt at a Solution
First i assume the diode 2 is open, but i don't know...
Homework Statement
Find the peak current in the circuit config:
V1 = 15v amplitude, 1khz freq.
R = 1.5k
Vd = 0.7v
Draw the transfer characteristic.
http://img341.imageshack.us/img341/9761/picture2ge7.jpg
Homework Equations
The Attempt at a Solution
Transfer Characteristic...
Homework Statement
Find the parameters of a piecewise linear model of a diode with the following known values:
v_d = 0.7V
i_D = 1mA
n = 2.
Make your model fit at 1mA.
Homework Equations
They are in the image below, written there.
The Attempt at a Solution
Here's my...
Good morning lovely people !
As I got some really helpful advice here yesterday i though i'd try it again, hopefully you haven't yet had too much from me (-:
So my question is concerning the attached PDF file (Last problem #3)
i am asked to find the current I_B in 3a) and 3c) but to my...
Hi everyone,
I don't have any homework question but I need help on a different thing:
I have to write a lab report on "Semiconductor Diode" ... so if you guys know any useful website that can give me some useful and important information (such as appliactions of semiconductor diode...
Homework Statement
A scheme of a diode circuit is attached. The voltages at the inputs A and B are 5V.
A. What is the output voltage (=voltage at the black node, Z)?
B. What values of resistance would you recommend for the resistor R?
2. The attempt at a solution
A. The diodes D1 and...
Hi! There's a schema of a diode AND gate attached. Could anyone of you, please, explain me why the voltage drop across the D1 diode is so big compared to the voltage drop across the D2 diode? Thanks a lot in advance!
Hi! http://www.phys.uAlberta.ca/~gingrich/phys395/notes/node71.html" 's an electrical network for a diode OR gate. It says there that "[t]he 12 V battery does nothing until the power fails; then it takes over without interruption."
I just wonder what electrical circuits (closed loops) are...
I have an interesting question about this circuit... if I were to calculate the voltage from point X to ground... essentially all it is, is voltage across the 4 kilo-ohm resistor because if it went the route of the diode, it would lose an additional 2.7 volts.. so its going to take the better...
I have to utilize a Curve Tracing machine on a 5V Zener Diode for a lab. The curve tracer shows voltage vs. current. The lab asks me to examine the curve and determine whether it is a Silicon or Germanium diode, but I'm wondering...what would be different about the graphs of the two types? Wont...
What type of circuit should one set up in order to induce chaotic outputs? My current research is pointing me towards a diode resonator circuit (resistor, inductor, diode in series) any ideas on that model or improvements from other research?
Hello,
In lab the reverse leakage current of 4 different diodes was measured. Then ranked from smallest to biggest. Then we are asked to decide which diode would be most suitable for charging up a capacitor and allowing the capacitor to keep its charge for the longest period of time?
I...
i am conducting research in chaotic behavior within diodes, can someone please direct me to the derrivation of the ideal diode equation and more importantly for my research, the calculation required for non linear activity in a diode such as that which occurs when the diode is over-reverse...
Hi,
everywhere I look for the equation describing the current of a diode, I get
I=I0exp(qvb/nkt-1)
n=1 for ideal case. for non-ideal diode you got values between 1-2.
in order to calculate n you have the equation: n=1+kt/(2*q*phi)
(phi=contact barrier height)
anyone knows how to...
Here is my question in the formation of Schottky Diode:
"Why does conduction band is lower than the original value in the semiconductor side?"
And I think it is lower because the postitve charged donor ions provide a attractive force ,which makes the electrons in semiconductor more easy to...
I'm trying to follow an example in the book that leads into more complicated circuits.
Consider a voltage source connected in series to first an ideal diode, and the diode is then connected (in series) to a capacitor. Let the input v_I be a sinusoid with a peak value V_p , and assume the...
Q:
In the circut below, I is a dc current and v_s is a sinusoidal signal. capacitors C_1 and C_2 are very large; their function is to couple the signal to and from the diode, but block the dc current from flowing into the signal source or the load (not shown). Use the diode small-signal...
For a PN junction diode, the total potential across the semiconductor equals the built-in potential minus the applied voltage.
Phi = Phi(built-in)-Va(voltage applied)
My question is what happens when the Va exceeds the Phi(built-in)? Will the Phi = negative? But how come they always...
Does anyone have any information on diode failure? I'm interested in knowing how diodes can fail and what happens when they do fail.
Specifically, what conditions of a diode will cause it to fail to be a closed circuit either direction criteria (like, become as useful as a wire)?
During the processing of a PN junction diode when the Ptype material and the Ntype material are joined together. The holes tend to diffuse from the Ptype material to the Ntype material and conversly the electrons from the Ntype material diffuse from the ntype material to the ptype material...
hey guys,
the topic basically explains it...Can someone please help me out with this question...How does SMPS differ from diode rectification?
Thanks
jake
Can you guys look at the attached file. I have a sensor hooked up to a plug box. My question is, i am suppose to control the sensor through labview. My question is, how does the diode play a role? I would technically send the commands to the 1st input right? and if i wanted to read data, i could...
Anyone knows where can I find graph(characteristics) of the 1N4148 diode.
Is there any website that has large number of different graphs for transistors, diodes ?