Voltage Definition and 1000 Threads

  1. John Pang

    Voltage drop in an electric circuits

    I don't understand why the voltage drops only when the charges in an electric circuitnpass through resistors or electric devices, but don't drop as charges move through the wire. As charges move through the wire due to electric potential differences, from a high potential to a low potential...
  2. M

    Voltage across reverse biased diode

    Hi all, I think I know the answer to this question but I'm having trouble explaining why it is so. If I have a circuit with a fixed resistor connected in parallel with a reverse biased diode, I believe the voltage drop across each will be the same. Is this correct? If so can someone explain the...
  3. A

    How does high internal resistance make high voltage power supplies safe?

    Homework Statement When the internal resistance is large in comparison to the external resistance, the terminal potential difference falls to a small value. This is used to make high voltage supplies safe for use in a laboratory. Explain how this makes the supply safe. Homework Equations...
  4. lucasLima

    Help calculating the voltage in a capacitor when t->infinite

    Hello Everyone! So, I need to calculate the voltage in the capacitor, let's call it Vc(t). For t=0- I know that there is no current in the capacitor. Did some calculations and I've found that Vc(0)=6v. Now i need to know Vc(infinite) But when the switch key is opened and the time goes to...
  5. kenok1216

    Kirchhoff's voltage law problem: Batteries, switches, resistors

    Homework Statement for S1,S2,S3,S4 are all closed at the long time find the current in each resistor Homework EquationsThe Attempt at a Solution why I3 is not = i2? the solution of this question is 24-28I1-I212-12=0 7I1-32=3-----(1) 12-12I2-163=0 3I2+43=3 ---(2) I1+I2-I3=0---(3) I1=0.492...
  6. M

    MHB Tutoring for voltage, charge, terminal voltage drop , temperature coefficient.

    I have several problems regarding this/these topics. Is anyone available to tutor me right now? Thank you.
  7. F

    Calculating R and C values given input and output voltage

    Homework Statement Homework Equations $$ V=IR $$ The Attempt at a Solution To simplify the algebra it was suggested that I set $$ R_{1}=R_{2}=R $$ and $$C_{1}=C_{2}=C $$ So that's what I did. I labeled the voltage in the middle node as $$ V_{1} $$Taking KCL at the middle node gives $$...
  8. B

    Determine voltage from a conductor in magnetic field

    Hi, I would like to know how to get the potential difference due to a constant local magnetic field acting on a wire moving at a constant speed perpendicular to the field. What is the link between F = q v ∧ B and the actual difference of potential in the circuit ? How to determine the induced...
  9. V

    Why do short circuits have zero voltage?

    I've searched around and all I can find are people quoting the equations. I see it in the math, but it seems contradictory. Here is my line of thought: 1. A source maintains a voltage difference across its terminals. 2. The difference in voltage causes charge to flow from higher to lower...
  10. alexandria

    Examining electric circuits and deducing current and voltage

    Homework Statement Homework Equations equations listed below in chart The Attempt at a Solution here is my answer, i just need to know if I am doing this correctly, thanks :)[/B]
  11. S

    Is My Battery Completely Dead?

    Homework Statement When a certain 9.0V battery is connected to a voltmeter, the voltmeter reads 8.00V (assume that the voltmeter has an internal resistance of 10MΩ. We may conclude that (A) only 1/9 of the battery's fuel has been used, and so the battery has plenty of life left in it. (B) the...
  12. Hassan Raafat

    Voltage Multiplier: Why Don't Current Divide Between Diodes?

    in Voltage Tripler and Quadrupler , why don't current divide between two diodes ( D1 , D3 ) or ( D2 , D4 ) ? they are forward in the same cycle , right ? I understand that charging happens in a very little time , so two cycles already is not shown on oscilloscope but in BoyleStad is explained...
  13. nfcfox

    Voltage in Parallel Circuits: Calculating Current through a Point

    Homework Statement {image inserted in-line by mentor} http://imgur.com/lnURBGX Calculate the magnitude of the current through point Y. Homework Equations Ohm's Law: V=IR Kirchoff's Junction: 1/Req=1/R+1/R2+1/R3+... The Attempt at a Solution I have been told that in parallel circuits the...
  14. Z

    Voltage output from DAC module, Obtaining the Pk-Pk Value

    I have a sine wave produced as an output, which varies. This sine wave has been filtered by a moving average filter. From this output, coming out of a DAC module, I need to obtain the the voltage peak-peak value and store it preferably in an array. How can I do this? More importantly how can I...
  15. P

    Deriving Capacitor Voltage for a Discharging Capacitor

    Homework Statement I'm trying to derive the voltage waveform across the capacitor for a discharging capacitor that has been fully charged by a DC power supply ##v_0##, i.e. ##v_c(t=0)=v_0## and then at ##t=0## the switch is flipped and the capacitor starts to discharge. Homework Equations The...
  16. ReidMerrill

    Peak Voltage across a capacitor.

    Homework Statement https://session.masteringphysics.com/problemAsset/1385140/3/36.P42.jpg Part A What is the peak current supplied by the emf in the figure? Part B What is the peak voltage across the 4.0 μF capacitor? Homework Equations I = V/XC = E0/1/2πfC = 2πfCE0 The Attempt at a Solution...
  17. G

    The peak-to-peak ripple voltage

    Homework Statement A 9 V power supply delivers 2 A to a resistive load. The a.c. supply is 230 V, 50 Hz and a bridge rectifier is used in conjunction with a 0.047 farad reservoir capacitor. Homework Equations Vpp = 1/(2FCRL) * VC The Attempt at a Solution 1/(2*50*0.047*2) * 9 =0.957v after...
  18. twiz_

    Maximum voltage from blowing through small turbine?

    If I had a turbine roughly 2 inches in diameter (4-5 blades), where the housing for the blades is about one inch wide (meaning the axle is 1"), what would be the estimated voltage I could produce if I were to use my lung power in one complete exhale through the input? That is, if there were...
  19. C

    Voltage induced by changing field

    5. A wire is formed into a 30 turn loop whose diameter is 14 cm and the resistance of the loop is 4 ohmns. The loop is placed on this page and a magnetic is going directly into the plane of the paper and is varying according to the formula B(t) = 4t^3 - 9t^2 + 3t - 28 Part (a): What is the...
  20. B

    Is My Op Amp Burned Out? Voltage Check

    The output voltage of op amp is greater than the power supply voltage (+/- 5V). Is Op amp burned out?
  21. Benighted

    How to interpret this circuit configuration? (Sensor bridge)

    So, I'm asked to demonstrate the formulas for finding out the voltage labeled here as ΔU, which I'm given in my project document: I think I would be able to make the demonstrations without any outside help, if only I knew how I'm supposed to interpret this circuit branch in the middle. Is it...
  22. 1

    Calculating voltage between two points....

    Homework Statement Homework Equations The voltage between any two points due to the field from a point charge q is: Kirchoff's voltage laws, which states that the total voltage around a closed loop must be zero, i.e.: The Attempt at a Solution To find V(e<-d) I used Kirchoff's...
  23. Jason Chuang

    Engineering TTL circuit voltage offset, why -2.5~2.5V and not 0~5V

    My teacher asked me to explain the reason why we need to tune the offset of the function generator of a ttl circuit to 2.5v(or -2.5v::didn't hear it clearly!) to create a shift from -2.5v to 2.5v instead of having it shift between 0v to 5v. I've done some research regarding the high voltage and...
  24. M

    Question about changing resistance and power

    Homework Statement So this was the question: The 60W filament lamp is connected to a 6.0 V battery. The resistance of the lamp in this circuit is 70 Ohms. Explain why this value differs from the value given in (a)(iv) when the lamp is connected to the 230V supply. My answer was: V=IR, P=IV...
  25. loki4000

    Electric dipole antenna voltage

    Homework Statement Greetings. Can someone give me hint how to solve following problem: Homework Equations From my understanding, you need following formula to solve problem: and then potential can be obtained by integrating over the current distribution. But right now these foormuas really...
  26. S

    How Do I Calculate Voltage Drop Without Knowing Current?

    Hi all Wondering if anyone can help. Really don't know where to start I know Zs = Ze + Z1 + Z2 and Z1 = PCR 8.9 milli-ohms/meter and Z2 = CPC 14.5 milli-ohms/meter which equates to 0.0234X milli-ohms/meter over X meters but where does my volt drop come in if I don't know my current? Regards
  27. S

    Short circuit current and Open circuit voltage -- Illumination

    Homework Statement I'm trying to understand the dependence of short circuit current and open circuit voltage on illumination. Short-circuit current is due to the generation and collection of light-generated carriers -- so does that mean the short circuit current is linearly dependent on...
  28. S

    Adjustable Voltage Regulator Output Voltage Range

    Homework Statement FIGURE 2 shows an adjustable voltage regulator using the LT1083 .The LT1083 develops a 1.25V reference voltage between the output and the adjust terminal. By placing a resistor R1 between these two terminals, a constant current is caused to flow through R1 and down through...
  29. Mr Davis 97

    How electric circuits really work

    I've been studying circuits, but I can't find any resources that really answer my specific questions. So far I understand that a battery creates a potential difference between the two terminals, one of which is positive while the other is negative. There is a buildup of positive charge on the...
  30. G

    Thevenin's circuit analysis. Multiple voltage sources

    Hi, i am halfway through one of my assignments and i require some assistance. I do not seek the answer to the assignment just a little boost to my knowledge. 1. Homework Statement Basically, if i am calculating the Thevenin's voltage and the resistor i have removed that is in question has a...
  31. L

    Voltage and Frequency Regulation (Grid, synchronous generation)

    Hi I was wondering if someone could help me understand and explain to me how one can control the frequency of the grid from help of the active power (frequency -> power angle -> active power) and how reactive power can be used to control the voltage level. My thoughts: Voltage Control: I don't...
  32. terryds

    What Voltage Makes the 6 Ohm Resistor Absorb 1.5 J/s?

    Homework Statement A circuit is arranged like above. To make the energy absorbed by the 6 ohm resistor every second is 1.5 J, voltage X should be ... Volt Homework Equations V = IRThe Attempt at a Solution [/B] I really have no idea. I just know that it's kinda like wheatstone bridge and...
  33. W

    Solving voltage divider involving capacitors

    Homework Statement Given ZV1 = ZV2 = 100Ω, ZCCV = ZCV = 2000/j = -2000j, and VV/VC = 0.04789. I'm trying to get the given VV/VC result. Homework Equations I know that 1/ZV = 1/ZV1 + 1/ZV2 + 1/ZCV VV = ZV / (ZV + ZCCV) * VC The Attempt at a Solution 1/ZV = 1/ZV1 + 1/ZV2 + 1/ZCV = 1/100 +...
  34. terryds

    Voltage Problem: Finding Unknown Voltage in a Circuit with Three Resistors"

    Homework Statement Three resistors (R1 = 3 ohm, R2 = 4 ohm, R3 = 5 ohm) is arranged like the picture above. The voltage at point 1 is 24 Volt and the voltage at point 2 is 10 Volt. The currents that go in R1 and R2 are 2 Amperes. The voltage at point 3 is ... Volt A. 10 B. 12 C. 16 D. 18 E...
  35. P

    Series resistors' output voltage

    In my electrical engineering textbook, in the section with voltage dividers, it says that after you combine two series resistors, then the output voltage can no longer be defined. It then said that thus the equivalence was made strictly from a voltage source standpoint. I do not understand why...
  36. loki4000

    Lorentz’s law of voltage for ac-generator

    Homework Statement Greetings So i was trying to solve following prolems: Homework EquationsThe Attempt at a Solution I did manage to solve problem 22 using E = NAB(2pi * f) E = (100)(0.005)(0.9)(2pi)(50) = 141.372 v But I have no idea what to do with problem 21. Mostly because I don't know...
  37. gustafangus

    How Can You Safely Discharge High-Voltage Capacitors Without Losing Energy?

    Hello, I have a bit of a problem with my project and it is as follows: I am trying to discharge a capacitor bank (2x 470uf 400V capacitors in parallel). I tried making a MOSFET switch to use that as a switch, but it kept burning out the mosfets (they were rated for 600V and around 100A), then I...
  38. A

    Non-contact DC Voltage detector

    How to build Non-contact DC Voltage detector/sensor?
  39. L

    Why are reactive power and voltage related?

    I have read that reactive power sustains/ supports voltage. What is the reason behind this?
  40. H

    Solve Equation (1) to Get Equation (2): The Depletion Voltage & Electric Field

    The electric field ...(1) by saying that ...(2)I tried to integrate equation (1) from r2 to r1 but could not get equation(2). Any suggesting. Thanks
  41. K

    Does electrical arc with the same power have same temp?

    Does electrical arc with the same power but different voltage and current have same temperature? When electrical arc is form, it is estimate that the temperature is about 3000K Does temperature depend on voltage or current alone? Or does it depend on power(P=VA)? I think it is power, because...
  42. G

    Calculating Voltage Gain Vo/Vi of an Op-Amp Circuit

    Homework Statement Determine the voltage gain Vo/Vi of the op-amp circuit Homework Equations inverting amplifer vout=-(Rf/Rin) x vin differential amplifer vout= (R2/R1) x (vo - vin) The Attempt at a Solution im really struggling to even get started with this one sorry for the limited...
  43. K

    What Does a Shifted Voltage Waveform Indicate About Load Characteristics?

    https://files.slack.com/files-pri/T0GNF95E2-F0TV5JSSG/voltage_reversed_and_shifted.png This the voltage waveform across a resistor load (15W). The applied voltage is 230V AC at 50Hz. What can be inferred from this? [ the Analog to Digital conversion of Voltage happens at around 1690 Samples per...
  44. C

    Electric Potential of a Point Charge close to R=0

    Homework Statement ≈ What is a 3D representation of voltage using Kq/r assuming a positive point charge and what is the equation in cartesian and cylindrical form2. Relavent equations Kq/r 3. Attempt at solution[/B] I was trying to get a better understanding of Voltage, to really FEEL...
  45. V

    Find voltage across resistor using mesh current analysis

    I'd like to find Vth by mesh current analysis. Mesh A and B share a current source, so they're treated as one supermesh. What's the equation for this supermesh? Also, do I ignore the loop with the open circuit? Since there's no current flowing there... 2A = ib - ia Anyway, is this the right...
  46. D

    How to solve a voltage issue in a 25 kva transformer?

    I need an urgent help. I have a 25 kva transformer in my house. Without load the volt metter indicates 114 volts. Which dould be fine for my house. But when I put the house on the transformer I have no electricity and the volt metter indicates less than 1 volt. Can anybody help me out please?
  47. M

    MHB Deriving the Voltage Equation: Using Kinematics to Show V=(mv^2/2q)

    Knowing that V=E(delta x), show that V=(mv^2/2q) I think I have to use kinematics and substitute some things but I'm not sure
  48. neilson18

    What is the voltage across battery terminals?

    Homework Statement [/B] Three resistors are connected to a real battery. The open circuit voltage of the battery is 4.5 Volts. The voltage across the 5 Ohm resistor is 2.5 Volts. A) What is the voltage across battery terminals? B) What is the internal resistance of the battery? Here's a...
  49. J

    Power Loss, Current, Resistors, and Voltage

    Homework Statement Consider the circuit shown below. a) What is the total power loss for the whole circuit? b) What is the power loss through R1? c) What is the power loss through R2? d) Find the voltage across each of the three resistors. I didn't do this myself. I have no idea what's going...
  50. P

    Complex Impedance of a voltage source and 2 resistors

    Homework Statement A real voltage source can be expressed as an ideal voltage source that is in series with a resistor that represents the inner resistance of the voltage source. This voltage source is a EMF and it is also in series with another resistor. Suppose both the EMF resistor...
Back
Top