I have a project that calls for activating a passive RFID tag by applying a few volts, and a PIN diode seems to be what I need. I can insert it into the antenna loop, where it would prevent an RF signal from being sent unless a forward DC voltage was present. I only know enough about...
What do i need to do for transfer characteristics for the first problem (B)?
I plotted the ##V_1## and ##V_2## plot on the same graph:
Is it correct?
For the second problem , i guess the capacitor ##C_1## is just there to ensure AC flow .
But really unsure how to approach this .
I have just started diodes .
What's ##V_{ON}## here? Could anyone explain what's going on in the graph? It seems like the one from the definition of half wave rectifier but shifted below the x axis by ##0.7##
This circuit has an ideal diode, which is modeled as
That is, when the potential difference across the diode is ##\leq 0## then we replace the diode with an open circuit and no current flows through it; when the potential difference is ##\geq 0## we replace the diode with a short circuit...
Hi all,
This is not homework help or something, it is my general query. I read that ideal diode equation is given as
in above equation Is is the reverse saturation current or dark saturation current (According to this website). And according to most of the study which I did this reverse...
Is the PN junction inside a diode what makes the electrical current only flow in one direction and not in the opposite direction? If this is so, why does it happen?
Also
Why is the P-type material said to have empty holes and the N-type material to have free electrons?
I have drawn the I-V characteristic graph of the diode. I am facing problems with drawing the load line. For what value of E (Source Voltage), should I draw the Load Line? To get the I-V graph, I had to continuously change E.
(a)
I know some of the apparatus needed for the experiment, such as DC power supply, ammeter, voltmeter, maybe rheostat. But I don't know how to change the temperature of diode. What is the correct and safe way to change the temperature of diode?
Thanks
In the circuit simulator there is no voltage at the Varactor cathodes when Vbias is zero, but depending on the Varactor I use on the breadboard it can be as high as 7.4 volts! There is minimal current through the series resistor when Vbias is applied in LTSPICE, but I always see a significant...
I would like to build a microscope witch can be used with different monochromatic light sources (laser diodes), and this system should has small astigmatic and coma aberration, but keep the chromatic aberration property. Can I use two spherical or ashperical lenses (facing with convex side to...
What I understand is that the β parameter of the npn transistor is temperature dependent. Increasing the temperature increases the collector current and hence the LED turns ON. But I don't understand the resistor arrangement.Also I can see that the diode is keeping the Base-Emitter junction in...
Hello everyone,
I don't know which laserdiode and lens system should I choose for my Project. It is all about AFM Microscopy with a cantilever ( Length= 450 um, width = 50 um and thickness= 2um). So as you see it is not a small cantilever. As far as I Know, the larger the cantilever is, a larger...
Hey all, I have a 5v IC that is triggered by a sensor to unlock the 12v lock, I am using a NPN transistor as a switch with the 5v VCC as the gate, I need it to sink back to the GND of the IC without blowing it, is this safe? If not what changes would you suggest, it has been years since I've had...
Hi there!
I have resolve this basic circuit, but, i have a little questions about.
The first circuit its:
The diode in all voltaje cases act like a switch, so, the courrent of all components and voltage of the resistance its zero. I graph the curve according my interpretation. My question its...
Option (A) and (B) is wrong because the waveform should be half-wave, not full-wave. But how to know whether it will be (C) or (D) based on the circuit given?
Thanks
Hi, all
I have a circuit where the base transistor (PN2222a) leg is plugged into the pin 9 of the Arduino. When I power everything up and send the signal from the Arduino to the transistor base leg, the laser diode doesn’t light up, but my design strictly follows Complete Tech Guide to Laser...
Hello! This is my first post.
Problem to use RF101 Diode: There is little RF 101 diode that I can search for.
And I have a project about the recovery circuit. but the frequency of the rectifier circuit is very low, it only has requirements for the withstand voltage. As long as the withstand...
I'm working with some bare chip diodes for an application where I need extreme luminosity. These are the diodes here:
https://www.irtronix.com/leuv-v625a6
I notice that some of the diodes have very significant resistance (on the order of megaohms) from anode to cathode and some have very small...
I've attached pictures with the circuit and part of the attempted solution. I've replaced the diode with its offset model and obtained the equivalent circuit in the 2nd picture. After applying KVL, I've obtained that u_l=−u_D−i_D*R. Since U_D0 is greater than 0, I've deduced that the diode must...
I am looking at modeling a PV cell and I'm trying to understand the real difference between the single diode and double diode mode. I now realize that I don't fully understand the purpose of the diode in the model in the first place. I've just learned that it was there and went with it. I...
Hello all,
I've just started learning about diodes.. I believe I've done this problem correctly (question in black), although want to make certain I'm understanding the very basics before moving on. Thank you
It's a mod to a weather station which normally uses primary cells alone. There are four cells, connected as 2X2. I am providing dc power up there for another purpose so I thought it may as well supply the station as well. But I need to protect / isolate the batteries from the DC source with a...
Hello there,
I've been working through a task (that doesn't have an answer sheet or explanation) in which we plot I against V for three different diodes. Each has a different threshold voltage and displays the usual charcteristic curve. The final question is this:
"It is suggested that the...
I have dismantled an old DVDRW drive and taken a 4-pin laser diode from it.
After connecting it to two 2A batteries (red with positive, and blue with negative), the light beam is diverging, and the brightness is even dimmer than another laser diode that I got from a presentation pen.
Also...
print ('Calculate threshold, power, slope efficiency for different lengths of SC Laser')
g = 510 # The gain of the laser, arbitrary value of 510 m^-1 was picked
I = np.linspace(0, 0.03,5) #DRIVE CURRENT; 100 values of current, 'I', between 0A and 0.03AV = 1.8 #INPUT VOLTAGE; arbitrary value of...
Unbiased circuit (no driving voltage source) **************
Fig 1
The N-type material has a tendency to donate electrons to the P-type (i.e. absorb holes from) across the PN junction via diffusion current exclusively within the conduction band of both materials. It does so after those...
This is really a nomenclature question.
The radiation pattern of a typical laser diode has one axis with low divergence (the slow axis) compared to the other (the fast axis). I understand about antenna radiation patterns, spatial Fourier transforms (Fourier optics), etc. So I think I understand...
I'm new to semiconductors.
While I was studying types of biasing in semiconductors, here's what I read -
'In forward biasing, the width of the depletion region is reduced.'
Here's what I thought -
Since the potential barrier is reduced in the junction due to external potential, the diffusion...
We are given that ##i_D = 8\cdot 10^{-12} (e^{v_D/20m} - 1)##
Hence ##i_D' = e^{50 v_D}/2500000000## and ##i_D'' = e^{50 v_D}/50000000##
Then I have that ##\delta i_D \approx\frac{ e^{50 v_D}}{2500000000} \cdot \delta v_D = \delta v_D / 5## Cancelling ##\delta v_D## from boh sides and solving...
i connected a diode to a 4 volt battery. in 1 direction the diode passes 4 volts. in the other direction the diode passes 1.9 volts. is this normal? shouldn't the diode pass 0 volts in the other direction?
So I have this circuit up above and I need to find the voltages across each of the diodes.
The only info given is that they are identical silicon diodes at T = 300K.
My first thought was that since the diodes are opposite, D2 would be in reverse bias and would act as an open. However, I realized...
i have been researching how to build a boost converter. according to the articles i have read, when the switch is closed current flows through the
switch to the negative terminal. when the switch is opened, the back emf from the inductor and input voltage add, which forward biases the diode.
i...
Ref: http://hyperphysics.phy-astr.gsu.edu/hbase/Solids/pnjun2.html
Hyperphysics Asstr
Why does the band diagram shift up or down when I apply potential? Why does it shift down when positive potential is applied? Professor said it's because electron has negative charge and so we consider...
Summary: Seek help with the working of a Capacitor in the presence of a DC & AC voltage source.
I greatly appreciate this opportunity to submit a question. It's a homework problem and I only seek to clear my concepts.
Problem: Find amplitude of the ripple voltage across the resistor...
In reference of Ned Mohan's book, I have designed a heatsink, firstly natural convection taken into account, but laboratory test results and theoretical calculations are not matching.
The test results:
For 40 A (means 62 W), 30 Celsius ambient temp, it raised up 51 Celsius. So, Rs-a =...
Hello,
In regards to this relay, TQ2SA-1.5V Panasonic 2 Form C AS Single side stable, 1.5VDC 2A DPDT NON-LATCHING SMD Relay
https://www.mouser.com/ProductDetail/769-TQ2SA-1.5V
PDF 1 of Relay
PDF 2 of Relay (specifically pages 5-6) is attached at the bottom as a pdf file.
I was previously told...
During high vacuum pumping, one sucks viscous gas out of a chamber down to just above the molecular flow density where viscous flow becomes absent, and then may employ a different sort of pump to start pulling in the remaining molecules: Molecular flow.
I have been wondering for a while if...
My project is to create a circuit for a stroller that can store the mechanical work into electrical while moving around and with the push of a switch, use the electrically stored energy to assist the movement of the stroller. I’ve tried capacitors but it ended up not being enough voltage and I...
Well I was just wondering how ohmic resistance works in a diode . I mean let's take forward bias mode.In forward bias mode electrons are diffused from the n type region to the p type region.The depletion layer still exists but is very narrow.So according to Drude model of ohmic resistance...
Assume we have a diode . We connenct the negative terminal of the battery(anode) to the n type region and we connect the positive terminal of the battery to the p type region of the battery.The net force forces electrons to start flowing from the n type region to the p type region.As long as we...
Assume we have a diode closed circuit.We connect the p type region of the diode to the positive terminal of the battery(cathode).We connect the n type region of the diode to the negative terminal of the battery(anode).The voltage of the battery is 0.3V .The diode%s intristic se miconductor is...
Assume we have a closed diode circuit .We connect the n type region of the diode to the positive terminal of the battery.We connect the p type region of the diode to the negative terminal of the battery.The depletion layer is increased.Now we open the circuit.Why the diode returns to its zero...