Junction Definition and 200 Threads

1. If two cells, one of 4.5V and one of 3V are connected in parallel what is the potential Difference across the junctions between them. 2. I = \frac{V}{R} 3. As 4.5v is greater it is the potential difference as they don't add up?

hi all i need a book about pn junction diode that starts from 0 and goes to 100. I've been reading solid state electronic devices by Ben G Streetman and elementary solid state physics by M. Ali Omar but these are too confusing and a lot of things are not explained like how some equations are...

please let me know how to cool the junction of thermocouple... is it possible to give current to both the wires n get junction cooled...?

is it possible that instead of heating the junction ... of thermocouple... we supply the current n the juntion cools down... which when touched felt cold... according to the supply of current...?? if not then is there any method of doing that

the formula for Vn should be V_n=(E_f-E_i)/q field divided by charge in the potential like i was taught in high school but why the write it V_n=(E_f-E_i)/KT k in the boltsman constant t is the temprature there multiplication cannot be the charge ?

Homework Statement I need to find the current equation for the junction in node a in the following circuit: http://i749.photobucket.com/albums/xx137/abcdmichelle/gjgjhg.jpg Homework Equations Current in = Current out so I(in)=I(out) The Attempt at a Solution The arrows in the...

Homework Statement A pn junction diode has saturation current Is= 1e-12 A. What is the current through this diode if a positive voltage 0.68 V is applied to it? (Unit: A) Homework Equations I=Is(e(Vd)/(Vt))-1) The Attempt at a Solution I don't even know where to begin, but i just...

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Homework Statement In the figure, what is the current in the wire above the junction? Homework Equations V=IR or I=V/R The Attempt at a Solution I am really confused as to what "above the junction" means. I tried to add the voltages and add the resistors and divide them to get...

Hi, I have a questions regarding semiconductor-metal junctions that has been left unresolved. I hope that you can offer me an explanation. I know that when a metal and n-doped semiconductor are in contact upward band bending occurs. This is because the Fermi levels in the two materials...

Hello All, I have very basic questions with respect to what we mean when we say a Transistor is in "Saturation". As I have read almost everywhere, we need to Forward bias both the emitter-base junction and Collector-Base Junctions for transistor to go to Saturation. Before I post my...

Hi, I'm learning Bipolar Junction Transistor and need help to confusion which arise so I will keep posting questions which I don't understand to this thread. Thank you in advance. So my questions start: When using hybrid pi model and t model, we determine the dc operating point first. In one...

I've got these two BJT circuits. I want to know if the result are the same. Are both circuits below same? Can the bottom left resistor be grounded and be same as the second circuit. http://img21.imageshack.us/img21/2886/bjtt.jpg

Hi, If we had two junctions one side with Nd=1016 & another side with Nd=1015 put together. What happens in such a junction? Would we see electron diffusion from the high donor concentration side to the lower concentration side? What should the band diagram of the junction look like...

"...Recall that the n-side is studded throughout with positively charged donor ions, fixed firmly in their lattice sites. Normally, the excess positive charge of each of these ions is compensated electrically by one of the conduction band electrons. When an n-side electron diffuses across the...

Homework Statement Forward resistance of the Base -Emitter Junction showed a value of 12ohms when it was measured by (x1) resistance scale of an analogue multimeter .And it showed 70ohms when it was measured using (x 10) scale factor .The variation in the two readings occurs due to...

Hey, I am working on a report and got stuck at two discussion questions. Help & discussion would be greatly appreciated! 1. What factors determine the turn-on voltage of a pn junction diode? Explain its dependence on the factors you mentioned My guess would be that the light intensity on...

Homework Statement One end of a nichrome wire of length 2L and cross-sectional area A is attached to an end of another nichrome wire of length L and cross-sectional area 2A. If the free end of the longer wire is at an electric potential of 8.0 V, and the free end of the shorter wire is at an...

Somewhere I read that the reason of halo doping in the MOSFETs is to increase the average doping of channel as the channel length is scaled to lower values. But I think there should be more about why is it done only at the source drain junction, and not somewhere else randomly like at the...

folks, when a pn junction diode is formed, electrons in the n type and holes in the p type diffuse. agreed. then how immobile ions are formed at the vicinity of the junction leading to depletion region? how these immobile ions prevent further diffusion? it is being said electrons and holes...

1. 1D heat conduction problem: Two rods, the first of length a , the second of length L-a with respective cross sectional areas A_1 , A_2 and heat conductivities k_1 , k_2 , are joined at one end. There are some boundary conditions on the other ends of the rods, but my question is only...

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 everyone. Is there anyone that can explane the band bending, whiche takes plane when a metal and a semiconductor are joined together? In illustrations of the band bending, it looks like that the energy of the valence and conduction band far from the junction have been lowered or raised...

Hi all, I would like to know how pn junction work? thanks DaTario

Homework Statement The information about the magnitudes of the current density and the diameters for wires 1, 2, 3, and 4 is given in the table. Some of the values are unknown. Wire Current density (A/mm^2) Diameter (mm) Total Current (A) 1-------- 1.6 --------...

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...

internel potentiel of PN junction?? so complicated homojunction PN (not polarized), externel potentiel difference applied = 0 Volt . i should demonstrate the equation: e*Vbi + Eg + ( Ec - Ef ) + ( Ef - Ev) = 0 Given: Vbi= internel potential Eg= energy gap Ef = Fermi...

I understand that for a semiconductor p-n junction under zero voltage, the Fermi level is constant throughout the junction because that is the condition for a system in thermodynamic equilibrium. I also understand that p-n junction under applied voltage (forward or reverse) is not a system in...

Any idea where I can fabricate a p-n junction of a custom length? I want it to be of a particular length and size, any company that can do it for me? How costly would it be?

I guess my most general question would be: Given a P/N junction. Let's say two circular discs, one P one N. There obviously exists some Vgap, and applying some voltage across it excites the electrons, then it emits light (very basic LED or something). Now, what if you took a piece of wire...

Homework Statement Consider a PNP Biploar Junction Transistor uniformly doped in each region. Sketch the energy ban ddiagram for the case when the transistor is biased in a)In thermal equilibrium b)biased in the active region c)biased in the cutoff (depletion) region Homework...

Hi I'm using thermocuple as a temp. sensor, it is inside soldering handle output is 0 mV (tested with digital voltmeter at range 200 mV) at room temperature. I'll amplify that voltage using AD623 I cannot use Ice bath to set ref. junction at 0 deg C. I thought using table (ref junction at 0 deg...

I have looked all over in many textbooks and I cannot find a decent explanation of this. Most textbooks simply say that it is independent of applied bias because all of the minority carriers generated by thermal energy within a diffusion length of the depletion region will essentially get swept...

Why is it that when no voltage is applied across the pn junction, the fermi energy is the same for both regions?

http://online.physics.uiuc.edu/courses/phys102/fall06/print_files/lect06_handout.ppt#10 Slide 10 How come the sign for R3 is not the opposite, shouldn't the postive charge be carried from E2 up to R3 making it + then -

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...

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...

the reversal potential is about 0mV, so how does opening the acetylcholine receptor at neuromuscular junctions cause action potentials to occur?

Hello all, I've been tasked with drawing the I-V characteristics of a silicon p-n junction diode and I've managed to do that fine. Now, I've been tasked with showing how this curve will vary with temperature (200-400 deg.c) and by illumination with light of photon energy greater than the...

A step pn junction diode is made in silicon with the n side having N'D = 2x10^16 cm^-3 and the p side having a net doping of N'A = 5x10^15 cm^-3. 1). Draw to scale the energy band diagram of the junction at equilibrium. 2). Find the built-in voltage, and compare with the value measured off...

I am confused here and hope to get help from you physicians..the assistant in the uni could not help me.. when we have a junction between two materials with different fermi levels, for example a metal and a semiconductor, we say the fermi level of the semiconductor gets shifted till it's equal...

I wonder do the genes have the same exon-intron junction sequences or do they have different junction sequences? I was told that all genes have this general junction sequences of the exon-intron-exon: 5'---exon---A/CG-><-GUPuAGU----intron-----Py12NPyAG-><-G---exon---3' The arrows indicate...

Hello. I use a kind of motion sensor located in a sealed metal enclosure. I perform temperature offset calibrating to this device, using an external temperature sensor (attached to the enclosure). This solves the most of temperature problems except when the temperature gradient is large -...

Hi Guys! How are u my friends? Well i want to ask u one important thing! Please tell me the way to find out the junction area of a diode Thanks in advance

Hi Guys! My Question is this: Dsign the circuit of the fig: so that Vo= 3V when IL = 0 A AND Vo changes by 40mV per 1mA of load current. the value of R = 4.8Kilo ohms. find the juction area of each diode (assume all four diodes are identical) relative to a diode with 0.7 V drop at 1mA...

when it comes to pn junction in diode, p and n are doping semiconductors. if P and N semiconductor are contacting each other, some holes in P and some electron in N are combined. that is, they are recombined. this recombination caused the current, very small. I was wondering that...

I have a peltier junction rated at 12V and when ran both sides become hot, what's wrong?

What's the physics behind a Peltier (sp?) Junction. I know what it does, but I'm not quite confident how it works. Paden Roder

How much does it cost? I'm thinking of buying one for a project. Where would I get one?

Hi, Does anyone know about the figure of eight crossover junction. I want to make a model toy where a cylinder is moving around the track completing the figure of eight, similar to model trains. How does one drive this cylinder around and how does it cross over from the circle of the eight to...