Electric circuit Definition and 201 Threads

An electrical network is an interconnection of electrical components (e.g., batteries, resistors, inductors, capacitors, switches, transistors) or a model of such an interconnection, consisting of electrical elements (e.g., voltage sources, current sources, resistances, inductances, capacitances). An electrical circuit is a network consisting of a closed loop, giving a return path for the current. Linear electrical networks, a special type consisting only of sources (voltage or current), linear lumped elements (resistors, capacitors, inductors), and linear distributed elements (transmission lines), have the property that signals are linearly superimposable. They are thus more easily analyzed, using powerful frequency domain methods such as Laplace transforms, to determine DC response, AC response, and transient response.
A resistive circuit is a circuit containing only resistors and ideal current and voltage sources. Analysis of resistive circuits is less complicated than analysis of circuits containing capacitors and inductors. If the sources are constant (DC) sources, the result is a DC circuit. The effective resistance and current distribution properties of arbitrary resistor networks can be modeled in terms of their graph measures and geometrical properties.A network that contains active electronic components is known as an electronic circuit. Such networks are generally nonlinear and require more complex design and analysis tools.

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  1. P

    Electric Circuit: Finding Unknown Resistance and EMF

    Homework Statement Three resistors and two batteries are connected as shown in the figure. The magnitude and direction of the currents in the unknown resistor "R" at the right and the 6.0 ohm resistor on the left are shown in the figure. The current in the 4.0 ohm resistance flows from B to...
  2. C

    Measuring Voltage with Distance in an Electric Circuit Lab

    I'm conducting a lab in which I change the distance of a lamp from a solar panel and use a multimeter to measure the resulting voltage. What type of relationship am I supposed to find? My results seem to indicate either a relationship with either a quadratic equation as its model or an inverse...
  3. H

    Electric Circuit. Norton Equivalent current

    Electric Circuit. Norton/Thevelin Equivalents Unsolved Problem I used a node voltage equation to try and get Vth and the I in the short-circuit to get the Rth but it didn't work. Unsolved Problem I used a node voltage equation to get Vth and I in the short-circuit. Got Rth and...
  4. T

    Electric circuit with resistors in series

    Homework Statement A battery , ammeter with resistance , 1 ohm and a resistor are connected in series .A voltmeter of 500 ohm is connected parallel to the resistor . The actual resistance of R is 100 ohm , what is the ratio of (the resistance R determined)/(the actual resistance of R) ...
  5. FeDeX_LaTeX

    Will current flow in a circuit with two opposing diodes and a DC source?

    Hi; Consider this circuit (ignore my bad drawing): http://img63.imageshack.us/img63/3967/diodes.png In the picture there is one cell, two diodes and a bulb. Will the current get trapped in the second branch and continuously flow around that loop? Thanks.
  6. T

    What is the resistance of the voltmeter in this series circuit?

    Homework Statement A 500 ohm resistor and a 1000 ohm resistor are connected in series with a 12 V battery of negligible internal resistance . When a voltmeter is connected across the 500 ohm resistor , its reading is 3 V . What is the resistance of the voltmeter ? Homework Equations...
  7. A

    How to calculate potential in an electric circuit with multiple batteries?

    How does one calculate the potential in an electric circuit when there are more than 1 batteries present? For example, in the circuit attached, how would we calculate the potential at A and B? Is it a simple addition? Thanks,
  8. S

    Electric circuit - time constant to charge

    Homework Statement Four identical capacitors are connected with a resistor in two different ways. When they are connected as in part a of the drawing, the time constant to charge up this circuit is 0.91 s. What is the time constant when they are connected with the same resistor as in part b...
  9. V

    Electric Circuit Question PLEASE HELP

    Homework Statement V = 1.2 kV C = 65 micro Farads R1 = R2 = R3 = 0.75 MegaOhms With C uncharged, switch S is closed (t = 0). At t = 0, what is the current through each resistor? At t = infinity, what is the current through each resistor? Homework Equations V= IR q = qo[1 - e^-t(RC)]...
  10. R

    How to Incorporate a Switch Activated by Zero Voltage in a Circuit?

    I have a circuit in which I have a constant voltage passing through until I hold down on a button at which point the voltage drops to zero. When I let go of the button the voltage returns to normal. I need to add to the circuit a switch which activates when a voltage of zero is passing through...
  11. C

    Electric circuit problem: Can you solve for V?

    Homework Statement find V=? http://img11.imageshack.us/img11/9152/dev1e.jpg Homework Equations The Attempt at a Solution
  12. R

    How Does Increasing Current Affect Charge Flow in Circuits?

    Hi, I just have a couple of circuit questions here 1. When we increase current in a circuit, does the charges flow faster or does more charges flow? 2. Does a resistor require electrons to pass through them or do they just require the potential energy of the electrons? Let's say if I add...
  13. F

    Electric Circuit Homework: Parallel & Series Heating Power

    Homework Statement Entrance exam question: An electric radiator which is an ordinary constant resistor emits a heating power of 750 W at a main supply voltage of 230 V. What is the total heating power in each respective instance when two such radiators are connected a) parallel, and b) in...
  14. Q

    Why Is My Calculation of Current in This Circuit Incorrect?

    Homework Statement http://img25.imageshack.us/img25/5953/elek.png Homework Equations v=IR The Attempt at a Solution I have tried finding the total resistance of the circuit and then applying ohms law. My answer is 0.65 Amps but that's incorrect. Any help is much appreciated!
  15. J

    Electric Circuit and Internal Resistance Lab

    Homework Statement I performed a lab where we designed an electric circuit on paper and then calculated the Current, Power, and Voltage for each of the resistors. We used one power supply. Then we built the circuit we designed and then measured the actual Current Power and Voltage for the it...
  16. E

    Electric circuit, reversing current

    Homework Statement Lets say that I have an electric circuit with an amp and volt meter attached to it and i reverse the direction of the current from the power supply.. what will happen to the reading of both the volt meter and the amp meter? Homework Equations The Attempt at a...
  17. E

    Currents in an series electric circuit

    Homework Statement Is the current at all points the same? If not then what is the order from highest to the lowest? http://img141.imageshack.us/img141/2418/currenthn9.th.jpg Homework Equations The Attempt at a Solution
  18. L

    Electric Circuit: Case I & II Solutions

    Homework Statement http://img88.imageshack.us/my.php?image=physicsxt0.jpg The circuit shown above includes a switch S, which can be closed to connect the 3-microfarad capacitor in parallel with the 10-ohm resistor or opened to disconnect the capacitor from the circuit. Case I. Switch S is...
  19. A

    Electric Circuit to solve with nodal analysis

    Can someone solve this circuit Find v and i in the circuit. I know that we have to make somethng with supernode, but where the supernode is here? How to develop this problem? Please help me :) Btw it is nice forum, today i have found that. I hope I will be able to help you in...
  20. A

    Electric Circuit Theory Concept

    Why do we take ideal voltage source to have 0 impedance and ideal current source to have infinite impedance. Please explain mathematically also!
  21. L

    Calculating Power and Voltage Drops in an Electric Circuit

    Homework Statement the questions quite big, but ill stick to the relevant parts power at the load, 35000W Voltage at load, 220V cable resistance = 0.1ohm field resistance = 60V The Attempt at a Solution the current at the load is P (load)/ V (load) = 35000/220 = 159A the...
  22. F

    First Order DE problem (electric circuit)

    (dq/dt) + (5/(20+t))q = 20/(20+t) ... t=0 , q=1 (a) Find the charge on the capacitor at any time. This is linear so i found the integrating factor which is (20+t)^5 and solved q(20+t)^5 = 20 integral ((20+t)^4) dt and got q(20+t)^5 = 4((20+t)^5) + C my C value i got was...
  23. R

    Electric Circuit Connected to Ground

    Homework Statement Given the attached scheme, if R_{1}=R_{2}=R_{3}=10 Ω and \epsilon_{1}=20 V , \epsilon_{2}=10 V determine the potentials at the points A,B,C,D,E. The sources of emf have no internal resistance. Homework Equations My question is: Why is it that no current exists along...
  24. S

    Finding angular frequency in electric circuit

    Homework Statement At a certain angular frequency, the phase difference between U_{2} and U_{1} is 180^{\circ}. a) Calculate this angular frequency b) Calculate U_{2} at this angular frequency See the attachment for circuit configuration. Homework Equations Ohms law: U = Z \cdot I...
  25. M

    Physics Rollercoaster- Simple electric circuit

    Physics Rollercoaster-- Simple electric circuit Hi all, I'm working on my physics rollercoaster project for grade 11 and I need a simple electric circuit to incorporate into it for more marks. At first I was thinking a circuit to bring the ball back up a hill when it reached the bottom but...
  26. C

    What Must the Output of the Powerhouse Be to Power the Factory?

    Hello. Hopefully someone here is able to answer this. I'm not sure if it's easy or hard, but it sure is frustrating... Here is the question...word for word, I would make a sad attempt at a picture, but it would probably be wrong. So... "A powerhouse near a waterfall has a large DC generator...
  27. I

    Electric Circuit Help (Emf and Internal Resistance)

    1. Find the current in, and the potential difference across, each resistor in the circuit shown below: The circuit is a simple parallel circuit with 2.0 ohms at the first resistor, 10.0 ohms at the second, and 20.0 ohms at the third The problem also gives you Emf which is 12.0 V and the...
  28. U

    Electric Circuit Homework: 3 Bulbs in Parallel & Series, 1 Burns Out

    Homework Statement 1. 3 light bulbs are connected parallel in the circuit ,one of them burns out .How this affects the other bulbs. 2. We have combination of parallel and series circuit(3 bulbs) and one of them R3 burns out . This gives us a series circuit with 2 bulbs .What happens to...
  29. S

    Energy transfers in an electric circuit

    ENERGY TRANSFERS IN A CIRCUIT: http://www.school-for-champions.com/science/images/elect_ohms_law-dc_circuit.gif LET VOLTAGE OF CELL IS 10V. Consider this: AN ELECTRIC FIELD IS SETUP IN THE WIRE. THE FORCE DUE TO THIS FIELD ACCELERATES THE CONDUCTION ELECTRONS IN THE WIRE. AN...
  30. R

    Electricity: Is a Closed Loop Always Required?

    IS Electric always a CLosed Loop? If Electricity pass through a Vaccum tube it is not a closed loop.. So can we consider it as a circuit?? also when we hold a charged conductor earthing take place... So charge flows through us.Can this be a circuit??
  31. H

    Electric Circuit HW: Find Potential Difference from Pass of Electrons

    Homework Statement The course that I am taking is so poorly organized. I keep having to do questions (for marks) for which I haven't even studied the principles yet. :mad: But anyway, I was hoping someone could help me with this, I assume basic, question about electric circuits. I studied...
  32. M

    Calculating Electron Potential Energy in a Thunderstorm

    During a particular thunderstorm, the electric potential difference between a cloud and the ground is Vcloud - Vground = 4.0 x 10^8 V, with the cloud being at the higher potential. What is the change in an electron's electric potential energy when the electron moves from the ground to the...
  33. N

    Electric Circuit Misconceptions

    There are a couple of things that just make no sense to me regarding circuits. Let me start off with my train of thought and how it leads into my questions, so someone can tell me where I go wrong. Question 1 (comes directly from a picture attached): A potential difference is setup...
  34. T

    Engineering Solving Electric Circuit: Calculate I(B) w/ KVL & Function

    http://www.savefile.com/files/7288537 find the current I(B) by calculation Use the current function and KVL the function is given as I(B)=0.01 (V(B) - 0.65V)^2 Can somebody pls show me the KVL ?? i tried to write the KVL as V(i) - I(B)R(i) - V(B) =0 then substitute into the function...
  35. B

    Where Can I Find Complex Electric Circuit Diagrams for High School Students?

    Hi everyone I have a hard time finding complex electrical circuits that high school students solve ...i.e. current, voltage and resistance within the circuit itself. If anyone can kindly find some of these complex electrical circuits to solve over the internet that can be any type series...
  36. H

    Problem with a electric circuit

    Problem-solved I have solved the problem
  37. F

    What is the current of the 8.0 ohm resistor in this circuit?

    http://img475.imageshack.us/img475/2209/scan0010015za.png I'm supposed to find the current of the 8.0 ohm resistor. I know that V=IR, P=IV, parallel circuits change in current and have constant voltage, and series circuits change in voltage and have constant current, but I get confused of...
  38. P

    Electric Circuit Troubleshooting: How to Find V6 and I6 | Expert Help

    Can someone help me and see if this is right and explain to me how to find V6 and I6? If you can, it would be great if you could explain to me the whole thing. Thank you:blushing:
  39. E

    What Happens to Voltage in an Electric Circuit?

    I need help with the idea of voltage as it relates to electric circuits. My book doesn't explain the concept well enough. All it says is that voltage is the force that moves charge through a circuit and overcomes resistance. Then it just states Ohm's Law, V=IR. Here are the things I don't...
  40. D

    How to Solve Electric Circuit Questions

    hey, i'm having some trouble finding out the TOTAL resistance of the circuit shown below, what i have done is: knowing its a combination series Rtotal = Rseries + Rparallel R4 + R3 + (1/R1 + 1/R2)^-1 and i got an awnser of 37.5 Ohms, but i don't know if i did this correct, some of my...
  41. C

    Electric Circuit Questions Answered

    Hello! I have a few questions that need answers. They are just simple thoughts. First of, its is said that the formula P = UI can applied to the energy being transformed every second over any component. But the formula P = (U^2)/R and the P= (I^2)R only can be applied over resistors...
  42. L

    What Is the Internal Resistance of the Used Battery in This Circuit Problem?

    Hello! I'm just preparing to write my physics 12 final and can't seem to solve a problem form a past exam that i was doing Here is the question: a circuit using a new battery which has an emf of 6.00 V and an internal resistnace of 1.00 ohms is shown on the left( In the diagram there also...
  43. W

    Electric Circuit Help: Finding Current and Voltage in a Complex Circuit

    Electric Circuit help! Ok here's my question: For the cirucit shown in the drawing(attached), find the current (I) through the 2.00 ohm resistor and the voltage (V) of the battery to the left of this resistor. Ok, should I be using Kirchoff's drop=rise, and junction rules? It doesn't...
  44. B

    Differential equation for a electric circuit

    ___ ___ /--|___|----|___|-\ | | | --- --- --- - --- --- | | | \-----------------/ So I've got an AC source at the left, 2 resistors (left one 2R...
  45. B

    Rate of heat generation in an electric circuit

    How can I find the rate at which heat is generated in the resister in an electric circuit connected to a 40-ohm resistor that is embedded in a .20 kg solid substance in a calorimeter. The external portion of the circuit is connected to a 60-volt power supply. I calculated the current and it is...
  46. C

    Solving Electric Circuit: Magnitude & Direction of Resistor 1 & 2

    Hello everyone. This problem has me stumped. The questioin asks, " find the magnitude (current) and direction of both resistor 1 and resistor2" (in the picture the top resistor is resistor 1) I know V=IR , but I am stumped at how the different potentials interact with eachorther at...
  47. L

    How Does Resonance Frequency Calculation Work in LC Circuits?

    This isn't really a homework question. I'm just trying to figure things out for myself about resonance in a circuit that they haven't taught us yet. Say you have a circuit Rp || L || C and you have a sine source and some load connected to it call it Re and you want to mesaure the gain. Vi...
  48. N

    Electric Circuit, drawing question

    I have to simplify this circuit step by step, and I'm stuck on how the first step after the drawing shown should look (how it looks after the resitances labeled 2 & 4 are combined).
  49. Q

    How is electrical potential transmitted through an electric circuit

    My question is how is electrical potential actually transmitted through an electric circuit. A charge (i.e. and electron) is moved through an magnetic field (as in a generator), the particle gains electric potential due to the work performed on it in the generator. This potential is then used...
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