Pd Definition and 48 Threads

  1. Sam Groves

    Function of PD, PI, ID and PID microcontrollers on a system

    Well different microcontrollers act differently on a system. A pure P microcontroller reduces the error and increases the final value , a pure I microcontroller nullifies the error and increases the final value and a pure D microcontroller increases the error and keeps the final value the same...
  2. sophiatev

    A PD code yields two different knot diagrams

    The PD code [(2, 3, 1, 4), (4, 1, 3, 2)] seems to map to a non-unique knot diagram. I can describe the following two Hopf links with different orientations with this same PD code. As I understand it, while a link diagram does not have a unique PD code, a given PD code should map to just one knot...
  3. duchuy

    Chemistry Solving H2/Pd/C Reduction for #5 & #6 Questions

    Hi, I'm trying to solve the number 5 and 6. Now I'm wondering what happens when I add H2/Pd/C on the 4th (after the question 4) molecule. I know that it will reduce pi bonds to sigma bonds, but will it affect the cetal group? Because if it does't I'm not quite sure that I'll be able to do the...
  4. M

    Pulse Duration (PD), Pulse Repetition Period (PRP) and Duty Factor (DF)

    I attempted this assignment, and scored a 5/10. The solutions are not given until a later date. I need to understand this material before I progress to the next section. The following are my attempts at the solution. The number of cycles in each pulse increases: The PD is determined by the...
  5. anemone

    MHB Parallelogram ABCD: Finding AC from PB & PD

    In parallelogram $ABCD$, $\angle B$ and $\angle D$ are acute while $\angle A$ and $\angle C$ are obtuse. The perpendicular from $C$ to $AB$ and the perpendicular from $A$ to $BC$ intersect at $P$ inside the parallelogram. If $PB=700$ and $PD=821$, find $AC$.
  6. A

    RF cavity shunt impedance, PD and input power

    I still did not understand this from my previous threads, what is the way to determine the instantaneous voltage across the cavity plates at any given moment, in a klystron I suppose the voltage would be proportional to the arriving electron bunch density which would determine the overall bunch...
  7. Theerapat

    PD pump (Rotary lobe pump) -- loud noise

    Hello, I have a problem with the rotary lobe pump, it causes a very loud noise when running. The pump specs are as follows: Liquid: Syrup (The liquid is in the 15,000 liters tank.) Viscosity: 2200 cPs Temp: Ambient Flowrate: 15 m3/hr Discharge pressure: less than 2 bar (open ended pipe) Inlet...
  8. Asmaa Mohammad

    Calculation of the least value of PD needed to produce x-rays

    Homework Statement [/B] In my excercise book, I was given a typical diagram as that in Fig (6-7) above. And the problem statement says: The diagram presents the x-ray spectrum produced by Coolidge tube. Determine the least potential difference needed to produce the characteristic radiation...
  9. J

    Hard Kirchoff's Laws problem with batteries & resistors....

    Homework Statement Homework Equations Kirchhoff;s first and second law, V=IR The Attempt at a Solution Tried the question as follows: V= 24/(2+6+4) = 24/12 = 2V (pd from top cell) then did 2=4 I3 therefore I3 = 0.5A and then 2 = 6I2 I2 = 0.33A and I1 = 0.5+0.33... =0.83A?
  10. moenste

    Calculate the speed of the electrons as they enter the gap

    Homework Statement Two parallel metal sheets of length 10 cm are separated by 20 mm in a vacuum. A narrow beam of electrons enters symmetrically between them as shown. When a PD of 1000 V is applied between the plates the electron beam just misses one of the plates as it emerges. Calculate...
  11. moenste

    Find drift velocity of the current carriers in the copper strip

    Homework Statement ABCD is a plane rectangular strip of conducting material of uniform thickness, with a steady current flowing uniformly from AD to BC. The potential difference between E and F, the mid-points respectively of AB and CD, is zero, but when a magnetic field is set up at right...
  12. moenste

    PD across the terminals of two cells

    Homework Statement In the following circuit, cell A has an EMF of 10 V and an internal resistance of 2 Ω; cell B has an EMF of 3 V and an internal resistance of 3 Ω. (a) Show that the currents through A and B are 65 / 71 amps and 14 / 71 amps respectively. What is the magnitude of the...
  13. moenste

    Why a lamp with X PD passes Y current

    Homework Statement A string of electric lamps for decorating a Christmas tree consists of 20 12 V lamps connected in series across the 240 V mains. The power consumption of the whole string is 24 W. (a) What is the resistance of each lamp? (b) If one lamp becomes short-circuited, what is...
  14. moenste

    Find current and PD across a circuit with diodes

    Homework Statement When answering the questions below, you may assume that the source resistance is negligible and that each diode has a potential difference of 0.6 V across it when conducting. For the circuit below calculate (a) the current in the 30 Ω resistor, (b) the current in the 60 Ω...
  15. D

    2nd Order Control system PD controller

    Hi, This question on PD control is from a practice quiz. 1. Homework Statement If you can't see it- the question asks to find values for Kp and Kd such that the system achieves 5% OS and has a settling time Ts of 3s. Cs = 3 Cd = 2 m = 5Homework Equations ω_n^2/(s^2 + 2ζw_n + ω_n^2) - 2nd...
  16. C

    Graphene energy dispersion & density of space relation PD

    Hello, What is the energy dispersion relation and density of states for graphen near the Dirac point ? I am looking for a proper graph illustrating these properties.
  17. S

    Rule of thumb for PI, PD and PID controller

    hello there, how to tune PI, PD and PID controller according to rule of thumb?
  18. J

    Optimizing PD Tuner Parameters for Improved Performance: A MATLAB Study

    Homework Statement So I have been asked to design a PD Controller on Matlab that satisfies certain performance criteria which are as follows : 1. The 10-90% rise time is less than 0.5 s 2. The percentage overshoot is less than 5%. 3. The settling time is less than 5 s I was given the closed...
  19. jake jungle

    What is the voltage across C2 in this circuit?

    Homework Statement Find the pd accros C2 Homework Equations Q=CV The Attempt at a Solution i find C23 = (C2C3)/ (C2 + C3) then find Q23 = V x C23 Q23 = Q2 = C2V2 => V2 i used this and got V2 = 15V , however the answer is 20V , and i even didnt use the data of C1 . am i wrong somewhere ?
  20. HeavyMetal

    Softness of Transition Metals Au, Ag, and Pd

    Is there a direct reason that gold, silver, and palladium are so much softer than the rest of the transition metals? Gold and silver are especially soft. I could not think of any reason myself, or in a quick search of the internet. Everything that I've come up with I've shot down. Thanks in...
  21. M

    Diodes in parallel with resistors and terminal PD

    1. Homework Statement The problem is not answering the questions, as supplied by the book The book then asks you to reverse both diodes, so you still have one diode in the circuit that let's current pass through it and one that does not. When you solve for the PD at Q you use the 0.6V...
  22. S

    Helping me to understand the difference between pd of a source and a component

    Hi, I've recently been reading up on circuit electricity and as the title states have found difficulty understanding the difference between pd of a source and a component from the textbooks I've been reading. So far I am to believe that the pd of a circuit is directly proportional to its...
  23. A

    Solving 2 Questions on Circuit Analysis: PD Across 3 Ohm & EMF of Batteries

    Homework Statement I have two questions. Both questions are in the picture below. Dont mind my workings lol http://img163.imageshack.us/img163/5680/scanpic0001qe.jpg Ans to the 1st qn: C The potential difference across the 3ohm resistor is zero. Thus, it can be considered that the 4ohm and...
  24. Τ

    Calculate Cell Potential at 25°C for Fe & Pd Cells

    Homework Statement Calculate the cell potential at 25°C for the cell: Fe (s) | (Fe^2+ (0.100 M) || Pd^2+ (1.0*10^-5 M) | Pd (s) given that the standard potential for Fe^2+/Fe is -0.45 V and for Pd^2+/Pd is +0.95 V. A. +1.28 V B. +1.16 V C. +1.52 V D. +1.68 V Homework Equations E Cell...
  25. R

    Spring-damper system as PD controller

    Why is this a spring-damper system considered to behave like a PD controller? The spring I am assuming would be the current error and so I guess the damper would provide information about the future error. How does the damper provide information about what the error will be in the future?
  26. J

    Describe how to show charge is proportional to pd on a capacitor

    Homework Statement Describe how you would show experimentally that the pd across a capacitor of fixed capacitance is proportional to the charge stored on the plates? Homework Equations The Attempt at a Solution So the most obvious thing would be to place a voltmeter in parallel to...
  27. I

    MHB More questions on psd and pd of matrices

    First question: If A is pd, then A^-1 is pd. Outline of answer: If A is pd, then there exists a nonsingular matrix P st A=P'P Then A^-1 = (P'P)^-1 = (P^-1) * (P^-1)' = (P^-1)' * (P^-1) 3. If (P^-1)' * (P^-1), then there exists a A^-1 that is positive definite Second question: If...
  28. I

    MHB If A is nnd, then show that I + A is pd

    nnd = non negative definite matrix pd = positive definite I'm having a tough time grappling with the concept of pd, psd matrices in general. My understanding basically just boils down to this, basically after multiplying everything out using the matrix formula x'Ax, you will get some sort of...
  29. S

    Acceleration through PD, relativistic momentum

    When accelerating an electron through a PD of 10^3, that will give a momentum of 1 MeV/c right? Or is there something I'm not taking into account with relativity? Thanks :D
  30. N

    Question about a PD controller.

    Hi, I'm taking a control engineering course and I've got a little doubt about PD controllers. Here is my root locus plot: http://imageshack.us/photo/my-images/535/controlw.png/ I have the system defined by the poles in the root locus with some design specifications that are satisfied when the...
  31. U

    Finding pd given r, R, and emf?

    Homework Statement What potential difference is measured across a 23 ohm load resistor when it is connected across a battery of emf 7.99 V and internal resistance 0.555 ohms Answer in units of V Homework Equations V=IR V=emf - Ir The Attempt at a Solution V=IR emf-Ir=IR...
  32. P

    PD (proportional derivative) controller

    All the books I have read say that when a proportional derivative controller is used the natural frequency remains the same. However, this is true only when the proportional part of the PD is unity. Otherwise the natural frequency is multiplied by Kp i.e. if the original...
  33. H

    Terminal PD vs EMF: When is PD Greater?

    when is terminal pd greater than emf ?
  34. H

    Calculating PD between +q and -q Charges at Points A & B

    Homework Statement Charges +q and -q at points A and B respectively separated by distance R. Required to calculate the potential difference between these 2 points. Homework Equations I want to do in two ways.. i.e once by integrating the electric field and the other by directly finding the...
  35. T

    How Does Oscillation Affect Capacitor Voltage After Multiple Cycles?

    Homework Statement A parallel plate capacitor is charged by a battery to 20 V and then disconnected . A simple pendulum consists of a metal bob which is suspended by a nylom thread is placed in the middle of the plates of the capacitor . Then the bob is oscillated towards the negative plate...
  36. H

    Electron accelerated through a PD

    An electron is accelerated from rest through a potential difference of 2 X 10^6 V. I need the velocity of the electron in order to calculate the energy of the particle. Using 1/2mv^2=u doesn't work because you get v > c. I can't seem to find an eqn to make the relativistic correction. Could...
  37. P

    Angle pd decay between two muons between Z boson?

    Question leads on from others where s^1/2 = 200GeV mH = 70GeV EH = 91.5GeV and p = 59GeV, (three momentum). The reaction was e+e- -> HZ0 where H is higgs boson and Z0 is the Z0 boson with mass 91GeV It says the Z0 decays to two muon and antimuon. They are observed to be equal energy in...
  38. G

    DCM+Methanol+10% Pd on Carbon generates HCl?

    I've been trying to remove a benzyl protecting group of a phenol and also remove a CBZ protecting group on a secondary amine by standard hydrogenation of the material with 10% Pd on Carbon. My protected molecule is very lipophilic and soluble in DCM. The reason I added methanol was because the...
  39. B

    Ripening Fruits: Tips for Planning & Design Lab Experiments

    I need to do my first planning and design lab but I need some general tips. The observation is that when fruits are wrapped in paper and put in a cupboard they ripen quickly. The attempt at a solution Now I have to come up with 3 hypothesis based on the obs. Am I right if I say: Fruits...
  40. J

    How to calculate NPIPA & NPIPR for PD pumps

    How do I determine NPIPA and NPIPR for PD oil pumps. I understand from limited research that suction condition is critical to the success of each application, but I do not know the formulas.
  41. N

    HELP - Derive 2-phase 3-dimesional PD flow equation

    Homework Statement Hello All, I'd please like some help in deriving a 2-phase 3-dimensional partial differential flow equation from first principles. Homework Equations I know that the starting point is Darcy's flow equation. The Attempt at a Solution A key step is substituting...
  42. V

    How Does Charge Increase Affect Capacitor Energy and Potential Difference?

    Homework Statement A capacitor of capacitance C stores an amount of energy E when the pd across it is V. Which line, A to D, gives the correct energy and pd when the charge is increased by 50%? Energy pd A) 1.25E 1.5V B) 2.25E 1.5V...
  43. M

    Calculating Potential Difference Between Points A and B

    Homework Statement a current of 2A is flowing from a to b. what is the potential difference between the points? ______a______3ohm_____-20V+_____1ohm_______+6V-________b_____ hopefully my diagram makes sense. Homework Equations this is a really simple question and i can't answer...
  44. L

    Root Loci of Double Integrator: PI & PD Controllers

    Homework Statement For the double integrator described with transfer function G(s) = \frac{1}{s^2} the initial condition is zero. The double integrator is subjected to a unit‐feedback system where the controller is chosen as 1) a PI-controller with C(s) = k_p \left( 1 + \frac{1}{s}...
  45. D

    Pd across resistors, can u explain the following?

    In a circuit that has a 12volt power supply and two 2- ohm resistors, R1 and R2, in series, the pd across each resistor is obviously 6v. If a 3rd resistor (also 2-ohm)R3, is placed in parallel across R2 then the pd across them changes to the following: R1=8v...
  46. G

    Pd cats. for Suzuki microwave rxn.

    I was wondering if any pro chemists on here have a decent amount of experience doing suzuki coupling reactions. Currently I am trying to couple alkyl boronic acids to a bromo pyridine in the microwave, but seem to be having a lot of trouble. The only thing that I am observing so far is removal...
  47. E

    Does Voltage Change When Resistance Drops in a Series Circuit?

    if i have two components in a series circuit and the resistance across one drops, does the pd across the other one increase?
  48. M

    Easy circuit question but i get the wrong answer for PD

    Hello everyone! I am stuck on this simple problem... A car battery with a 12 V emf and an internal resistance of 0.050 is being charged with a current of 60 A. (a) What is the potential difference V across its terminals? wrong check mark V (b) What is the rate Pr of energy...
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