Resistor Definition and 894 Threads

  1. B. Vane

    RCL Circuit: 2 Resistors, 1 Capacitor, 2 Inductors

    Homework Statement NOTE: Image uploaded with thread shows problem in clearest possible form. V = (45v)sin(80[pi] t) Resistors 1 and 2 = 50 Ohms Inductor 1 = 20 mH Inductor 2 = 2.5 mH Capacitor = 50 uF a) Find the power dissipated by each resistor. b) At what frequency will both resistors...
  2. B

    Average power dissipated in resistor

    Homework Statement Find the average power dissipated in the 30 Ω resistor in the circuit seen in the figure if ig=7cos20,000tA. Homework Equations KVL/KCL equations P=VI* (possibly) or I^2(R) The Attempt at a Solution I tried to do a mesh, but got I∆(60-j130) = 0, which isn't right . . . I'm...
  3. D

    Please help clarify use of resistor in this circuit

    Hello everyone. I'm trying to teach myself how electronics work and I've ran into some questions with this circuit. This is from Make:Electronics experiment 10. I understand R2 is resisting the flow to the gate so the transistor doesn't fry. I also understand R3 will restrict flow to the LED...
  4. BeautifulLight

    Can you stop current flow with a resistor? And POTs?

    This thread will concern the workings of potentiometers, but I could use some help tackling something first. I will explain in my next post! Assume I have shorted out a battery with some resistor. I always thought that if you had a high enough resistor value, you could stop current from...
  5. C

    Variable resistor & inductor connected to alternator

    A simple 2 pole alternator (a synchronous generator), is powered by a steam turbine. The amount of steam to the turbine is kept constant with a constant pressure ##p##, flow rate ##\dot{q}##, and power ##P##. If a variable resistor, inductor, and capacitor are connected in series to the...
  6. S

    Finding the current Io for t>0 in a RL circuit

    Homework Statement For the circuit in the attached file, find io (current) for t>0 Homework Equations The Attempt at a Solution I have included an attachment which shows the solution. However, I will copy the solution here as well for reference: When t<0, the switch is closed, the inductor...
  7. R

    Resistor Problem involving Lightbulbs

    Homework Statement We have 6 lightbulbs that are identical attached to a battery, and we need to list them from brightest to dimmest. This is what they look like. Homework Equations None...? The Attempt at a Solution So, my thinking is that bulbs 6,1,2 are the brightest and the same...
  8. A

    Resistor network and 2 voltage sources, help sought

    [Mentor note: thread title reworded] R = 1.00 k and = 250 V in Figure P28.25, determine the direction and magnitude of the current in the horizontal wire between a and e. http://www.webassign.net/pse/p28-23.gif I found a solution online...
  9. D

    Resistor Network Circuit Analysis

    Could someone help me with number 1. I think I did it wrong. I attached the diagram with the labels. On the original one the resistors aren't labeled, but I separately labeled them on my diagram. 1. R1=1.0 ohms R2=3.0 ohms R3=5.0 ohms R4=12 ohms R5=2.0ohms R6=4.0 ohms R=0.2 ohms...
  10. S

    Finding the equivalent resistance of an RL cct & step input

    Homework Statement Determine the inductor current i(t) for both t<0 and t>0 for the circuit shown in the attached document"Circuit 1. Homework EquationsThe Attempt at a Solution Before t=0, i=(25)/(3+2) = 5A After t=0, i(t)=i(0)e^(-t/tow) tow=L/R=4/(6/5) However, the...
  11. Essence

    Voltage loss w/ resistor scaling with current

    So according to the ideal voltage loss equation V = IR if I double I (per se) I will double the loss in voltage. This is a bit odd and I just want to make sure my intuitive explanation is correct. I am assuming voltage loss is mainly due to some electrons bouncing off the resisting material and...
  12. S

    Phase Difference between Voltage and Current

    Homework Statement The circuit above has a 29 resistor and a 11.1 mH inductor. Calculate the theoretical phase difference between the current CPA and voltage VPB if the circuit is driven by a sinusoidal voltage source with a peak amplitude of 3.5 V at the following frequencies: 20 Hz 420 Hz...
  13. R

    How Long Does It Take for a Capacitor to Charge to 8V in an RC Circuit?

    Homework Statement A 8500 Ω resistor is joined in series with a 80 μF capacitor. a) What is the capacitive time constant of this combination? (Solved: 0.65 s) b) If a 9.0 volt battery is suddenly connected across this RC combination, how long will it take for the capacitor voltage to reach 8.0...
  14. S

    Engineering Finding the component values of a RLC circuit

    What methods could I utilise to find the individual values of the components - resistor, inductor and capacitor - of a series RLC circuit using an oscilloscope, signal generator and 10 ohm resistor. Where each component can be isolated in order to find the voltage etc. I've already found the...
  15. G

    Find Maximum Power to Resistor R

    Homework Statement Homework Equations Pmax = ((VTh)2)/(4RTh) Rparallel = (R1R2)/(R1 + R2) KCL ΣI = 0 KVL ΣV = 0 The Attempt at a Solution Okay, so to find RTh, I remove all independent sources and set the "terminals" at R to have a 1A current running through them. Since there is a 30kΩ...
  16. X

    Why is the voltage across one resistor the same as supply?

    People say that the voltage across one resistor is equal to the voltage supplied. I've drawn a picture of a simple circuit with two points near the positive terminal. Apparently, if we take the potential difference of these two points, it will equal 9V according to the above saying (which can...
  17. S

    What is the importance of the upper resistor in this circuit

    The book also says you can increase the time delay by increasing the resistance of the upper resistor , why, what does it do? uploading images
  18. mooncrater

    Can Symmetry Simplify a Hard Resistor Network?

    the question is , to find the net resistance across the points a and b as marked in the figure(attached).Here I think that the method of Symmetry should work . But I am not sure about it and moreover its not clear to me how to use it.The Attempt at a Solution
  19. G

    Unknown value of added resistor in parallel

    Homework Statement Picture provided. The current going through the resistor R1 in the figure does not change whether the two switches S1 and S2 are both open or both closed. The resistances are R1 = 14.00 Ω, R2 = 142.00 Ω, and R3 = 24.00 Ω. The voltage is V = 11 V. With this information, what...
  20. acdurbin953

    Given voltage, solve for unknown resistor in a circuit

    Homework Statement An ohmic resistor (R1 = 3.5 kΩ) and circuit element X are connected in series to a battery of unknown voltage V0. Circuit element X is of unknown resistance. It is observed that the absolute value of the voltage across resistor R1 is 5.0 V. The battery voltage is measured and...
  21. P

    Power dissipated by a resistor in a circuit

    Homework Statement Homework Equations P = V^2 / R 1/Rt = sum(1/Ri) (parallel) The Attempt at a Solution [/B] Since all the answer choices express the solution in terms of V^2 / R, I tried to find the voltage drop across resistor #2 to find the power. I collapsed the two parallel...
  22. jcoona

    Resistors Used in College Electrical Circuits Labs - Any Suggestions?

    I am taking an intro electrical circuits course which requires that I write extensive lab reports. I just completed a really simple lab about calculating resistance when configured in series and parallel, etc. In my intro I'm writing a short explanation about resistance, and resistors, and...
  23. jake jungle

    DC current -- Find the 3 currents in this Battery + Resistor circuit

    Homework Statement Find I1 , I2 and I3 Homework Equations I = E / R I3 = I1 - I2 The Attempt at a Solution its the trouble with parallel different emf . I know a formula how to combine them into one but it needs inner resistance . i don't know how to do it with the ideal circuit . The...
  24. S

    General DC Circuit: Voltage drop different from supply source

    Homework Statement I performed a lab with a simple DC circuit. The circuit has 4 resistors (i.e. R1, R2, R3 and R4), which is the same as shown in the attached image. When the voltages across all resistors were added, they were higher than the source. How is this possible? The KVL rule states...
  25. hideelo

    What happens in a simple circuit with an EMF and a resistor?

    Imagine a simple circuit, an EMF connected to a resistor which connects back to the EMF. This is how I'm thinking about it I know there is a current which means that there is charge moving around the loop which means that there must be some field because otherwise the charges wouldve never...
  26. S

    Does metal film resistor work at cryogenic temperature (3K)?

    I am trying to use a metal film resistor to limit the current inside a dilution fridge (to reduce noise power from it), but I couldn't confirm if the metal film resistor is going to survive (or it goes superconducting) at ~3 Kelvin, searching a bit on the web but still I couldn't find the...
  27. J

    Will Current Pass Through a Resistor in Parallel with a Wire?

    If a "normal" looking wire and a resistor are in parallel on a simple circuit diagram, will any current pass through the resistor?
  28. J

    Maximum resistance and power for LED

    Homework Statement You wish to use an LED (D1) which provides essentially zero resistance and is rated to accept either a maximum of 75 mW of power or 30 mA of current. In the following two circuits, what range values for resistor R1 will be acceptable in each case if the voltage provided by V1...
  29. U

    Power dissipated by a resistor in combined citcuit

    Find the power dissipated by R2 given that V a-b=120 volts, R1=1, R2=3.33, R3=2, and R4=3 I've worked this problem, just want to confirm I worked it correctly. A---------R1-----------*------------------- | |...
  30. L

    Determining voltage across resistor and current direction

    Homework Statement Resistor conected to unknown network N. Resistor immersed in isolated water bath. Resistor resistance R = 8 ohms. It is determined the power dissipated in resistor is 11 W a) Find the voltage across the resistor. b) What is the current i entering the network N from the...
  31. A

    Find resistance of resistor in RC circuit

    Homework Statement Find the resistance of resistor R7 when the switch is turned on so that the power of that resistor is maximum in the circuit. The voltage of the capacitor before the switch is turned on is Vc=200V. Homework Equations Thevenin's theorem The Attempt at a Solution I...
  32. H

    What Wattage Rating Is Needed for a 33Ohm Resistor in a 9V, 1A Circuit?

    Hello, I am new to any type of engineering and just have been working with Arduinos and other microcontroller lately for fun. I am creating a prototype for a project that requires me to use a 9V power supply with 1Amp to power the Arduino(note, the arduino only needs around 300mA to run). I...
  33. N

    Calculate electric current in a resistor

    Homework Statement calculate the electric current in the 20 ohm resistor The Attempt at a Solution I have no idea where to start, but i thought maybe you should calculate the voltage first and then the voltage over the 20 ohm resistor.
  34. W

    Engineering Tough Circuit Problem, Find Current When Switch is Closed

    Homework Statement I got questions a) and b), but I'm stuck at c) and d). Homework Equations Kirchhoff's Loop and Junction rules. Equivalent resistance in series: Req = R1 + R2 Equivalent resistance in parallel: Req = ((R1)-1 + (R2)-1)-1 The Attempt at a Solution I really haven't gotten...
  35. T

    Why is resistor power maximum in parallel with same value?

    Hello, I want to ask the explanation for this basic problem. So I have 2 resistors in parallel(X and Y) and I want to maximize the power going through the resistor X, by choosing the resistance. This can be achieved only by choosing the same resistance for X, than Y has. Why is this so? I can...
  36. M

    Difference between wirewound resistor and inductor

    Hi. I am looking to understand the difference primarily in construction between a wirewound resistor and an inductor. Both are formed using a coil loop but are clearly behaving differently. Does the coil in a wirewound resistor induce a magnetic field?? Thanks, Mark.
  37. C

    Power wasted/delivered to a resistor

    Homework Statement two 8 ohm resistors and a battery of emf 12.0V and internal resistance of 8ohms are connected in series. Calculate the power delivered to each external resistor and then calculate the power wasted due to internal resistance. I keep coming up with the answer 18 but apparently...
  38. C

    Power dissipation limit for a resistor

    I am confused about the concept of a power dissipation limit for a resistor. Basically for a resistor the product of the current through it and the potential across it should not exceed 0.25 watt otherwise it starts to heat up and act in a non-linear fashion. Is this value just a constant or is...
  39. C

    The current through an individual resistor

    The following circuit has been modeled using some modelling software (Micro-Cap 11). I was wondering why current is only shown at the source and not in R1, R_Unknown and R3. I know current is meant to be the same in series although I am confused by the effects of the resistors. (This is not a...
  40. R

    What is the current through each resistor in this circuit?

    Consider the circuit shown in the figure . Suppose the four resistors in this circuit have the values R1 = 12 , R2 = 6.0 , R3 = 7.3 , and R4 = 15 , and that the emf of the battery is E = 18V . (1) Find the current through each resistor using the rules for series and parallel resistors. Answer...
  41. A

    Independent Current Source In Series With Resistor

    Homework Statement Write the KVL Equation for the outer loop Homework EquationsThe Attempt at a Solution The question above is a sample I have made for such a condition. The goal is not to find the value, but only write the correct equation. If an independent current source is connected in...
  42. zug

    What is the minimum wattage rating the resistor should have?

    Homework Statement [/B] The question "What is the minimum wattage rating the resistor should have?" comes after a previous problem I did to determine the maximum and minimum current when given a resistors tolerance. Here are all the values from that problem, some aren't really important but...
  43. M

    Voltage and current in a resistor

    So I know that voltage is a sort of pressure due to an imbalance of charges. And current is the resulting flow of charges. So when it comes to a resistor, does the resistance draw a current from the curcuit as well as a voltage? And what is meant by "voltage drop" across a resistor/element...
  44. B

    Circuit Segment (Two sources with a resistor in between)

    Homework Statement If a current I=4 A exists between points a and b, R1=6 http://loncapa.mines.edu/adm/jsMath/fonts/cmr10/alpha/100/char0A.png, R2=6 [PLAIN][PLAIN]http://loncapa.mines.edu/adm/jsMath/fonts/cmr10/alpha/100/char0A.png, V1=16 V, and V2=6 V,the voltage difference Va−Vb isHomework...
  45. E

    Indeoendent current source in series with a resistor

    Guys, this seems very trivial yet I can not come to the correct answer and I've searched everywhere. I am asked to find the node voltages using nodal analysis. The trouble is I don't know how to express a current in a brach between 2 unknown voltages where there is an independent current...
  46. Undacuva

    Understanding High Power Resistor Ratings: A Beginner's Guide

    Hi, I'm looking for a high power resistor. I just got confused over some nomenclature I haven't seen before. (Yes I'm a beginner). I'm seeing resistors named like this: "3R9ohm"and "4R7ohm" I know what R is in V=IR. But in the rating of a resistor? Can someone help?
  47. A

    Engineering Circuit theory -- Current source, voltage source, resistor in series

    Homework Statement the voltage Vc in the figure is always equal to 2 Relevant equations The Attempt at a Solution From kirchhoffs law, -Vc+4+5=0 Vc=9 V will Vc always equal to 9 V or it will vary?
  48. A

    How Does Adding a Resistor Affect Power Dissipation in a Parallel Circuit?

    Homework Statement You have a circuit with a single resistor of resistance R connected to a battery that has zero internal resistance and has a power output of 12W. A resistor of resistance of 6R is now connected in parallel to the original resistor. How much power is now dissipated in the...
  49. Ellie

    Current through resistor parallel to two different batteries

    Homework Statement I'm sorry that I have no pic, but please bear with my description. The circuit diagram is made up of 3 horizontal lines. On the top line, there's battery A, (-) on the left, (+) on the right, and an arrow going to the right (>) to show direction of current. On the...
  50. Rugile

    Heat in a resistor (circuit with inductor and capacitor)

    Homework Statement A source of ε = 10V, capacitor of C = 5 μf, inductor of L = 15 mH and r = 10 Ω and a resistor of R = 100 Ω are connected as in the schematic (attached). How much heat will dissipate in the resistor after the switch is opened? Homework Equations dQ = I2Rdt KVL The...
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