What is Resistors: Definition and 603 Discussions

A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines, among other uses. High-power resistors that can dissipate many watts of electrical power as heat, may be used as part of motor controls, in power distribution systems, or as test loads for generators.
Fixed resistors have resistances that only change slightly with temperature, time or operating voltage. Variable resistors can be used to adjust circuit elements (such as a volume control or a lamp dimmer), or as sensing devices for heat, light, humidity, force, or chemical activity.
Resistors are common elements of electrical networks and electronic circuits and are ubiquitous in electronic equipment. Practical resistors as discrete components can be composed of various compounds and forms. Resistors are also implemented within integrated circuits.
The electrical function of a resistor is specified by its resistance: common commercial resistors are manufactured over a range of more than nine orders of magnitude. The nominal value of the resistance falls within the manufacturing tolerance, indicated on the component.

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  1. archaic

    Current Through R1 and R3: Explained

    Hey guys, in the picture below, the current flowing through R1 is the same flowing through R3 right? And hence we have R1 and R3 in series? In this second picture R2 is going to cancel out because apparently that's what happens when you have a branch containing components parallel with a wire...
  2. Islam Sabry

    The equivalent resistance for the resistors in this circuit?

    Homework Statement If the circuit of parallel and series resistors , is as follows , what's the equivalent resistance for the group? Homework Equations neglecting the battery internal resistance... irrelevant to the question. The Attempt at a Solution I tried to do the following R1=8+12=20...
  3. Beanyboy

    Build Astable 555 Timer 8-Bit Computer Clock with Ben Eater's Project

    Am trying to build an Astable 555 timer 8 bit computer clock. Ben Eater's project. Resistors are specified, but with no reference to wattage. Does anyone know the appropriate wattage for the carbon film resistors please?
  4. Santilopez10

    Circuit problem involving sources and resistors

    Homework Statement The currents ##I_{{a}}## and ##I_{{b}}## of the circuit have values 4A and -2A in that respective order. A) Find ##I_{{g}}## B) Find the power dissipated by each resistance C) Find ##V_{{g}}## (voltage drop across the current source) D) Show that the power delivered by the...
  5. M

    Resistors - Current equal in Series

    Hello, I've been googling about this topic and have read from a number of different books but I still haven't found an exact answer to my question. It is known that the current is equal when the resistors are in a series. But the resistors per definition reduce current flow. If there are 2...
  6. C

    Engineering Simple transformer circuit with 3 resistors

    Homework Statement 2. Homework Equations [/B] V1N2=V2N1 I1N1=I2N2 The Attempt at a Solution For a part[/B] I try to draw 3 mesh but I cannot write down the equation. Can someone help me out?
  7. G

    Weird circuit board with only resistors

    Found this. What could it be? So many resistors and nothing else?
  8. K

    Method for testing discharge resistors in 3 phase capacitors

    A couple of months ago I was troubleshooting a blown fuse on a power factor correction capacitor in a 4160v motor starter. While I was working through it I noticed that my DMM (fluke 289) would charge the capacitor to a certain degree while on the Ω function. The current from the meter would...
  9. D

    How to calculate the resistance in a combined circuit

    Homework Statement Work out the total resistance of a combined circuit. https://gyazo.com/935b96ff63689e2bff852f29ea48bf90 - picture of circuit layout Homework Equations Rt=R1+R2+Rn... R=V/I 1/RT=1/R1+1/R2+1/Rn... The Attempt at a Solution RT=R1+R2 =100+150=250Ω for the resistors in series...
  10. A

    How to calculate voltage drop

    So I have two formulas for calculating voltage drop. The first is: Vdrop = Vin * R1 / ( R1 + R2...). This let's me calculate the voltage drop on the first resistor in a series of 2 resistors. You can also extend this to more resistors in series just by summing all the resistors. However, I do...
  11. M

    Current in circuit with many resistors

    Homework Statement Find the current and potential difference through 3Ω resistor. Homework Equations ε - I1 (Ω) - I2 (Ω) ... = 0 The Attempt at a Solution I only got as far as finding the equation: ε - I1 (3Ω) - I2 (16Ω) = 0 (For complete loop around circuit) I know I have to find I1, but I...
  12. E

    I with this circuit -- 2 resistors and 2 sources....

    Homework Statement The problem is in this link https://www.chegg.com/homework-help/find-vo-io-circuit-fig-226figure-226-chapter-2-problem-7pp-solution-9780078028229-exc Homework Equations 3. The Attempt at a Solution [/B] 15=[io/3]+[io/3]+ [vo/12] I got this equation for the problem...
  13. Richie Smash

    Positioning of Resistors in Series

    Hi, I'm aware that the total resistance in a series connection is the sum of all the resistors involved, and that the current is the same throughout, and that the voltage will be different for each resistor but the total voltage will be their sum as well. However, I would like to inquire, does...
  14. E

    Is the textbook wrong or am I? (circuit with resistors, switches and a battery)

    Homework Statement This circuit is given:[/B] Each resistor has a resistance of 30Ω, and the electrive force is 28V. Now we shut S1, and the voltmeter displays a value lower by 10% from the previous one. What is the internal resistance of the voltage source? What is the voltage between the...
  15. G

    What about the electric field in a circuit with resistors?

    Hi. I am having some trouble understanding what is the voltage drop in a system with resistors in series. If there is a difference of electric potential between two points in space, since electric potential is electric potential energy per charge, there is a difference in the electric...
  16. T

    Engineering How can I simplify this mixed resistors circuit

    Hi I am to calculate Rab of the circuit and I have no idea on how to approach this problem. It would have been all nice and eaasy if it weren't for the vertival 30 ohm resistor. Because of this I'm in a dark spot. I will appreciate any help.
  17. G

    3 resistors in parallel: how to get there

    Homework Statement 2. Homework Equations [/B] Hi! So I was given the following circuit with R=15k I was asked to calculate the equivalent resistance between A and B. The Attempt at a Solution [/B] According to my professor this circuit is equivalent to a circuit with three resistors in...
  18. P

    Engineering How Do You Solve RCL Circuit Problems Using Kirchhoff's Loop Rule?

    Homework Statement I'm just really lost on this topic and honestly don't have too much of an idea. (a) Using Kirchoff's loop rule, find the differential equation satisfied by the charge q(t). (b) Verify that q(t) = q_max e^-(a/t) cos(ωt) satisfies the differential equation for particular...
  19. S

    Resistors in Series - Lab data confusion

    Homework Statement (see my attached photo to better understand where I am coming from!) So after some research, I've discovered that the current at different points in a simple series circuit is supposed to be the same value, and that the voltage is supposed to be different values. I...
  20. S

    Resistors in Series - Lab data confusion

    Hi guys! (see my attached photo to better understand where I am coming from!) So after some research, I've discovered that the current at different points in a simple series circuit is supposed to be the same value, and that the voltage is supposed to be different values. I performed a lab on...
  21. G

    What Causes Maximum Joule Heating in a Resistor Circuit?

    Homework Statement 2. Homework Equations [/B] Consider the following circuit where: $$R_A=330 k\Omega$$ $$R_B=220 k\Omega$$ $$C= 2.2 nF $$ $$v_1(t)=6u(t) V$$ $$ i_2(t)=-10u(t-t_2) \mu A$$ $$t_2 = 12 ms $$ All the currents go clockwise (with the obvious exception of the current source)...
  22. L

    Resistance dependance on temperature for ohmic resistors

    Hello, I was giving a random thought to Ohm's Laws and thermal dilation. As a general rule we are told that ohmic resistors will increase their resistivity if their temperature increases. Does this take into account the fact that its dimensions will change due to thermal dilation? This would...
  23. shihab-kol

    How Do You Calculate Total Resistance in Mixed Resistor Circuits?

    Homework Statement 2. Homework Equations [/B] ## V = IR ## The Attempt at a Solution My solution: R1,R2,R3 are in parallel and so we can find their total R ## \frac {R1×R2×R3}{R1+R2+R3} = R'## ##R' = \frac {10}{3}## R' is in series with R4 ## ∴ R= R' + R4 = \frac{10}{3} +10 =...
  24. wolram

    Where Can I Find Dale Resistors?

    Can anyone give me a source for these resistors please?
  25. T

    Arranging resistors to have a minimum equivalent

    Homework Statement The minimum resistance obtained by connecting 50 resistances of 0.25 ohm each is A)50/4ohm B)4/50 ohm C)200 ohm D)1/200 ohm 2.Relevant equations 1.When resistances are connected in series, ▪R(equivalent)=summation of all individual resistances 2.When resistances are...
  26. W

    How would you solve the following cuircut problem?

    Homework Statement You are tasked with designing an electrical circuit with a motor, a battery, and several 1ohm and 2ohm resistors. The motor is designed to run at a current of 20A and a voltage of 10V, but your battery supplies 15 V. The motor can then lift a 4kg mass 2.25 meters in...
  27. C

    Power of resistors in parallel vs series circuit

    Homework Statement Two Ohm's resistors in parallel consume power of 76 W and 24 W. What power will each of them consume if transfer them to the serial circuit with the same voltage of source. Sorry for my bad english translations I m not use to writing questions in English.. So what confuses...
  28. A

    Circuit Problem -- Combining 4 resistors to make 95 Ohms

    Homework Statement 1. Use resistors of 30 ohms, 40 ohms, 50 ohms, and 50 ohms to create a circuit with a total resistance of 95 ohms. 2. Find the amount of current going through two of these resistors if the circuit is attached to a source of 12 v. 3. What would be the voltage drops for the...
  29. L

    Why Do I Need So Many Resistors? Is It Possible to Reduce?

    Hello. I wonder if I can take some of these resistors off and make the signal stronger without breaking the rest of the components. Is this possible? Also why are the non-trimming capacitors needed? I have a picture attached. Thank you!
  30. Ali Zain

    Rank in order, from largest to smallest, the resistance (eq)

    Homework Statement There is a figure, I'll try my best to draw/describe. 1. All three resisters are in parallel ___R____ !___R____! !___R____ ! 2. 2 resisters are parallel and one in series, after the parallel (ignore the dots) ___R___ ... _____R___ !___R___ ! 3. 2...
  31. Vanessa Avila

    Finding the current through the battery

    Homework Statement I am confused what to do but I have to find the current through the battery: Homework Equations V=IR The Attempt at a Solution I decided to find the equivalent resistance and do V/R = I using the 14V, but I believe my Req is wrong. What is throwing me off is the...
  32. egio

    I Not sure what I can make into equivalent resistors

    Could I combine the two resistors together in parallel to make an equivalent resistor, and then use that equivalent resistor in series with the capacitor? It would be great if there was some rule of thumb that I can use to know what I can make into an equivalent resistor/capacitor down the line...
  33. Shayan shan

    Potential In parallal combination of resistors

    Why is the Potential Difference equal in parallel combination of resistances ?
  34. jlmccart03

    Find ratio of diameter of two Cylindrical Resistors?

    Homework Statement Two cylindrical resistors are made from the same material and have the same length. When connected across the same battery, one(A) dissipates twice as much power as the other(B). Find ratio of dA/dB. Homework Equations P = VI = V2/R = I2R Area of cylinder = 2πrh + 2πr2 The...
  35. P

    Circuit is constructed with six resistors and two batteries

    <Moderator note: Thread moved from technical forums hence no homework template is shown> A circuit is constructed with six resistors and two batteries as shown. The battery voltages are V1 = 18 V and V2 = 12 V. The positive terminals are indicated with a + sign, The values for the resistors...
  36. Hamood97

    Find the two figures and the get value of the resistor and current

    Homework Statement finding the resistor and current which is following through the circuit[/B]Homework Equations kirchhoff law The Attempt at a Solution almost as fig 1 ( 9v=3.458 mA and 12v=11.122 mA) fig 2 (9v=1.472 mA and 12v=12.882 mA) i3=2.48 mA
  37. franktherabbit

    Delta-Y transformation of resistors

    Homework Statement Starting from the expression of the Delta-Y resistor transformation work out the conductance transformation equation. Homework Equations 3. The Attempt at a Solution [/B] I will just be using one equation as others are done analogically. My Δ has ##(R_{12},R_{23},R_{13})##...
  38. doktorwho

    Engineering Total power of resistors in a circuit

    Homework Statement In this problem we are asked to calculate the total power of the resistors in the circuit below. Homework Equations ##P=I^2R## The Attempt at a Solution My solution goes like this: PT=PR1+PR2+PR3+PR4+PR5 I can find PR1 and PR5 immediately from the given current...
  39. solour

    Reducing all circuit resistors to only parallel and series?

    Homework Statement The problem from the textbook is: Is it possible to connect resistors together in a way that cannot be reduced to some combination of series and parallel combinations? Homework Equations V = IR kirchhoff's current law kirchhoff's loop law The Attempt at a Solution I am...
  40. F

    Circuit question with two batteries and resistors in pa

    Homework Statement [/B] Q: What is the power dissipated by R1? Homework Equations Ohm's law: V = IR Power: P = VI, I2R, V2/R Kirchoff's circuit and voltage laws The Attempt at a Solution I assumed the currents were I1 traveling rightwards from the top battery, I2 rightwards from the...
  41. franktherabbit

    Engineering Transformation of resistors in a circuit

    Homework Statement From the circuit diagram ( http://postimg.org/image/lldnr7mf7/ ) calculate the net charge flown through the capacitor 2. Homework Equations 3. The Attempt at a Solution [/B] I actually don't need to solve the full problem as i understand how, what i have trouble with is the...
  42. B

    Reducing voltage with two resistors

    Homework Statement An electric potential of 5.0 V is required to run certain computer chips. A 6.0 V battery may be used to do this but it must be connect to two resistors in series. Supposing one has a resistance of 330 Ohms what should the other be? (The computer chip will be driven by the...
  43. I

    What is the resistance between two resistors?

    Homework Statement Homework Equations R=V/I The Attempt at a Solution Would it be 10ohms? Since PQ is between two 10ohms resistor.
  44. 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?
  45. Biker

    Electrical circuits with resistors and variable voltage sources

    Homework Statement The following picture illustrate how the current in the circuit changes when you change ##E_2##. Where slope 1 represents the current flowing through ##E_1## and slope 2 represents the current flowing through ##E2## Homework Equations Usual circuit laws :P The Attempt at...
  46. B

    Are the resistors in series vs in parallel?

    Homework Statement A metal wire of resistance R is cut into two pieces of equal length. The two pieces are connected together side by side. What is the resistance of the two connected wires? Homework Equations RSeries = R1 + R2 + ... RParallel = (1/R1 + 1/R2 + ...)-1 The Attempt at a Solution...
  47. BiGyElLoWhAt

    Current flow direction in "infinite" cube of 1ohm resistors

    Homework Statement Write a program to find the equivalent resistance between two opposite corners within a grid of "infinite size" with resistors between each point. So basically we have an infinite cube made up of cubes with 1 ohm resistors between each node. Homework Equations Kirkoff's laws...
  48. C

    A circuit with multiple sources of voltage

    Homework Statement Solve this circuit: a) Mark all currents b) Write a system of equations allowing you to solve for the currents2. The attempt at a solution Part a) in attachment. Part b) \epsilon_1 = i_1 r_1 + (i_1 + i_2 + i_3) R \epsilon_2 = i_2 r_2 + (i_1 + i_2 + i_3) R \epsilon_3 =...
  49. Passionate Eng

    Heating Resistors: Current & Voltage for Temp Control

    if I heat a resistor, it will reach a specific temperature and keep it. because as temperature increases the resistance decreases, so reducing the power absorbed. is that true? and how to calculate how much current and voltage I have to deliver to reach a specific temperature?
  50. M

    Engineering Solving Circuits with Resistors: Finding Req and Applying the VIR Chart

    Homework Statement https://s10.postimg.org/lb6n94ua1/20161007_190700.jpg Homework Equations V=IR The Attempt at a Solution So far I haven't had any problems finding the Req. However, I am having trouble with the VIR chart. Can anyone confirm whether or not I did it correctly. My thought...
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