What is Parallel circuit: Definition and 109 Discussions

Two-terminal components and electrical networks can be connected in series or parallel. The resulting electrical network will have two terminals, and itself can participate in a series or parallel topology. Whether a two-terminal "object" is an electrical component (e.g. a resistor) or an electrical network (e.g. resistors in series) is a matter of perspective. This article will use "component" to refer to a two-terminal "object" that participate in the series/parallel networks.
Components connected in series are connected along a single "electrical path", and each component has the same current through it, equal to the current through the network. The voltage across the network is equal to the sum of the voltages across each component. Components connected in parallel are connected along multiple paths, and each component has the same voltage across it, equal to the voltage across the network. The current through the network is equal to the sum of the currents through each component.
The two preceding statements are equivalent, except for exchanging the role of voltage and current.
A circuit composed solely of components connected in series is known as a series circuit; likewise, one connected completely in parallel is known as a parallel circuit. Many circuits can be analyzed as combination of series and parallel circuits, along with other configurations.
In a series circuit, the current that flows through each of the components is the same, and the voltage across the circuit is the sum of the individual voltage drops across each component. In a parallel circuit, the voltage across each of the components is the same, and the total current is the sum of the currents flowing through each component.Consider a very simple circuit consisting of four light bulbs and a 12-volt automotive battery. If a wire joins the battery to one bulb, to the next bulb, to the next bulb, to the next bulb, then back to the battery in one continuous loop, the bulbs are said to be in series. If each bulb is wired to the battery in a separate loop, the bulbs are said to be in parallel. If the four light bulbs are connected in series, the same current flows through all of them and the voltage drop is 3-volts across each bulb, which may not be sufficient to make them glow. If the light bulbs are connected in parallel, the currents through the light bulbs combine to form the current in the battery, while the voltage drop is 12-volts across each bulb and they all glow.
In a series circuit, every device must function for the circuit to be complete. If one bulb burns out in a series circuit, the entire circuit is broken. In parallel circuits, each light bulb has its own circuit, so all but one light could be burned out, and the last one will still function.

View More On Wikipedia.org
  1. K

    Equivalent resistance in a parallel circuit

    Homework Statement Prove that the equivalent resistance in a parallel circuit with 2 resistors with resistance R1 and R2 is always lesser than the resistance of either resistor. Homework Equations Rt= (R1 x R2)/(R1 + R2) The Attempt at a Solution I tried starting from R1 + R2...
  2. P

    Is this the right way to find Zeq for parallel circuit

    Homework Statement http://www.flickr.com/photos/84781786@N03/8687383259/in/photostream/ Homework Equations Vc=Vsource*Zeq/(200+Zeq) The Attempt at a Solution Is this the correct way to get Zeq 100Ω and inductor as series . so we 100+j100 parallel with the capacitor. which...
  3. D

    Parallel circuit multiple choice question

    This past Monday I took an exam and got a 99, woot woot! But I can't seem to understand why I got the following question wrong: Complete the following statement: A simple series circuit contains a resistance R and an ideal battery. If a second resistor is connected in parallel with R, A) the...
  4. P

    Capacitor in a Parallel Circuit

    Homework Statement I'm not sure how to put this in words, but I shall try. Alternatively, I've attached an image. It's hand-drawn, but I hope it's legible enough. Imagine a circuit drawn in the shape of a rectangle, with a single resistor ##R_1## on the top side, plus a DC cell...
  5. E

    Why is voltage the same in a parallel circuit

    I am wondering why are voltages the same across a parallel circuit. How can we say that it depends on the start and end points only. On what basis? Thanks for clarifying!
  6. M

    Finding Resistance in a Parallel Circuit

    So there is a parallel circuit with two resistors, R1 and R2, and an ammeter that are connected to a constant 30-volt source. The equivalent resistance of the circuit is 6.0-ohms. The resistance of R1 is 10.-ohms. The resistance of R2 is equal to a) 6.0 Ω b) 2.0 Ω c) 15 Ω d) 4.0 Ω...
  7. J

    Potential difference in parallel circuit

    Homework Statement I am currently revising some AS level Circuit modules and I'm having trouble seeing how the P.D across 3 components in a parallel circuit can each have the same value as the P.D of the battery. I am probably just being dumb but its just not making sense! such as this...
  8. J

    Simple parallel circuit question

    Ok so my maths department decided to give us a question about electrical circuits with no information on how they work. Considering that more than half of the students are only starting their physics study this year (including me) it seems a bit odd... I just need a bit of clarification on a few...
  9. G

    Engineering RLC parallel circuit phasors and current

    Homework Statement Sorry for the stupid question, but I want to be sure whether everything is correct. Here is the problem, I think I managed to do all the parts. 2. The attempt at a solution a)ω=2∏f; ω=4000∏ or 12566.37 rads b)Xl = ωL = 4000∏x0.004=50.27Ω c)I1=R x Vac I2=Xl x...
  10. K

    Engineering Terminals within a parallel circuit question

    Homework Statement Here's the circuit in question http://s52.beta.photobucket.com/user/I_eat_corn/media/circuit1.png.html I need to calculate the voltage at terminals A, B, C, and D. (A and B are finished and checked) Homework Equations Ohms Law, E=IR, I=E\R, R=E\I, P=VI or RI^2 The...
  11. G

    Resonance in LC(R) parallel circuit

    Homework Statement I did an experiment as followed Given following circuit I measured voltage across capacitor and reciprocal frequency of the generator. espilon, L, C, R, and R_E were given. In one configuration, R was shorted. I have to calculate relative frequencies (gamma)...
  12. B

    Compound Circuits and resistance in a parallel circuit

    Homework Statement http://imageshack.us/a/img829/1351/circuite.png Find the current through R3 and R2. The resistance of R2 and R3 are 3.00 Ω, so the total resistance should be 9.00 Ω. I = 80.0 V / 9.00 Ω = 8.89 A Homework Equations I = E/R (I think?) The Attempt at a...
  13. N

    How Does Frequency Affect Impedance in a Parallel RLC Circuit?

    A 1000 ohm resistor, 500 picofarad capacitor, and 2 millihenry inductor are all conducted in parallel. What is the impedance if the frequency is 10 kilocycles per second? 10 megacycles per sec? At what frequency is the absolute value of impedance the greatest? I know I start by considering...
  14. U

    Measuring obstacle size in a parallel circuit of different lengths of wire

    Homework Statement In lab, we were instructed to create a circuit that uses nichrome wires and identical bulbs to measure the obstacle caused by an object. To do this, we slid the alligator clip along the nichrome wire until the 2 bulbs in parallel are the same brightness. The object that we...
  15. Y

    Distinguishing series & parallel circuit

    This is a general question. I'm having a hard time distinguishing complicated series and parrallel circuits. For example, in the picture, how do you simplify the circuit?
  16. D

    Parallel Circuit: Current with 4 vs 3 Resistors

    Hey I came across this question in my textbook and the answer provided just does't make sense. A circuit consists of a battery and 4 identical resistors in parallel. The current in each resistor is 12 A. If one of the resistors burns out, what will be the current in each of the remaining 3...
  17. J

    Question: Are the capacitors in series or parallel in this circuit?

    We are shown a circuit diagram as in attachement It shows an open switch and two capacitors (both of which have been charged fully in previous experiments Question: The capacitors are joined as shown in the circuit. When switch S is closed the voltage across both capacitors is the same...
  18. K

    Engineering Finding the frequency of a series parallel circuit using complex notation

    The frequency, ω, of the source in the circuit of Figure 2 is adjusted until ig is in phase with vg. (a)using complex notation, determine the value of ω (rad/sec) Can anyone out there please help with this question? I've tried multiple methods but I am really struggling with simplifying the...
  19. BruceW

    Power dissipation in parallel circuit

    Right, so I was going over some old (basic) electromagnetism principles (to make sure it doesn't all fall out of my head). And I was thinking about two resistors in parallel, assuming some constant dc voltage across them. And I was thinking about the power dissipated by this simple circuit. And...
  20. A

    Finding current through in a specific part of a parallel circuit.

    Homework Statement In this circuit E1 = 5.98 volts and E2 = 4.45 volts. To the nearest hundredth of an amp what is I1? I have attatched a picture Homework Equations V=IR 1/Req=1/R1+ 1/R2+ 1/R3 The Attempt at a Solution Well I think I know that resistance for the whole...
  21. S

    Engineering RL parallel circuit. No value given

    http://img849.imageshack.us/img849/9894/photo1zvk.jpg Uploaded with ImageShack.us Guys I'm very new to this subject. This is 1 of my question form assignment. a) find Vab(magnitude and angle) b) plot magnitude of Vab against XL c) find the active power dissipated in each resistor...
  22. A

    Total Current in RLC Parallel Circuit

    Homework Statement Hi Can a kind person please check my solution? This is the question: Demonstrate the total current in an RLC parallel circuit using the following circuit. I can't draw it but the inductive reactance is 20ohms, capacitive reactance is 5ohms and resistor of 10ohms. All are in...
  23. C

    Series and parallel circuit with multiple resistors?

    Series and parallel circuit with multiple resistors?? Homework Statement If R1 = 27Ω and R2 = 7Ω : a. What is the equivalent resistance of the circuit? b. What is the current from the battery? c. What is the voltage drop across the R1 resistor? Homework Equations I=V/R ΔV=-IR...
  24. K

    Three light bulbs in parallel circuit and Currents

    Homework Statement Pretend you have three light bulbs in a parallel circuit and one light bulb goes out/removed so that there two light bulbs remaining. Does current of the entire circuit increase, remain same, or decrease after the one of the bulb is removed. The answer is decrease...
  25. C

    Engineering RL parallel circuit & vector problem

    Hi I have been working on this problem and would like to know if I am close to being correct, I am also having difficulty understanding the difference between knowing when to use (vector and magnitude of a vector) relationships correctly, I give an example of this below. A inductor and...
  26. N

    Series and parallel circuit question

    SERIES CIRCUIT QUESTION Given: R1 = 24 Ω R2 = 8 Ω R3 = 60 Ω Homework Question: a) Which resistor would have the greatest current passing through it? Explain. b) Which resistor would have the greatest potential difference across it? Explain. PARALLEL CIRCUIT QUESTION given...
  27. L

    Capacitors: Why is this a Parallel Circuit?

    Two capacitors are connected in parallel to each other and a battery. There are two switches, S1 between the first capacitor and the battery and S2 between the two capacitors. At first, S2 is open and S1 closed, so the first capacitor charges, then S1 is opened and S2 closed, so the charge is...
  28. S

    Calculating Time Constant and Voltage Decay in a Parallel Circuit

    Two 500μF capacitor are connected in parallel, and then to a 100kW (105W) resistor. The capacitors are momentarily charged using a 1000V D.C. supply. Find: a) The time constant of the circuit. b) The time “t” taken for the capacitor voltage to decay to 630 volts c) The current in the...
  29. S

    Parallel Circuit 2 batteries, solving for current of resistor

    Homework Statement For the circuit shown in the figure below, calculate the current I4 through the 2.18 resistor. As shown, R1 = 4.20 R2 = 8.12 R3 = 6.10 R4 = 2.18 I1 = 3.16A and E1 = 18V I couldn't get the picture on here but I will describe it: It is a parallel circuit, with...
  30. P

    Unexpected change in potential difference across a parallel circuit

    Hello, I have just completed a physics lab in which I was trying to prove that the potential difference across a parallel circuit remains constant regardless of how many resistors are connected in the circuit. The potential difference of the battery is 6V. As I connected the resistors, starting...
  31. O

    Two Resistors in a Parallel Circuit

    Homework Statement Two resistors of X and Y are in parallel with one another and in series with a 200 Ω resistor and a battery whose emf is 1.5 volt and whose internal resistance is 0.5 Ω. The resistance of X is 100 Ω. When Y is disconnected from X, an additional resistance of 50 Ohms must...
  32. G

    Simple Parallel Circuit Problem

    Homework Statement I have to find V0 and I0. [PLAIN]http://img842.imageshack.us/img842/3058/resistor.png Homework Equations I am having trouble identifying parallel resistors. The Attempt at a Solution So far I think that the 70 ohm and 30 ohm resistors are parallel but I am not...
  33. R

    Calculate Battery Energy Delivery Rate for Parallel Circuit

    Homework Statement A current I9 = 2 A flows through the 9 ohm resistor. At what rate does the battery deliver energy to the entire circuit? Homework Equations There are 3 resistors in the circuit, all wired in parallel. r1=15 ohms, r2=12 ohms, r3=9 ohms The Attempt at a Solution
  34. A

    Finding Req in parallel circuit

    Hi. I am having problems finding the Req in parallel circuits. I have a problem like this R1- 12 R2- 8 R3- 8 emf- 12 Now I know Req= 1/R1, 1/R2, 1/R3 but my homework book explains that 1/12 1/8 1/8 = (2+3+3)/24 = 8/24 = 1/3 = Req is 3 coulomb I...
  35. K

    Potential Difference in Series and Parallel circuit

    Ok I'm new here. I'm only a seconday student, recently exposed to Physics. I have a few doubts and questions on the chapter Electricity. Why is the potential difference same for all the bulbs in a parallel circuit? My teacher only seems to explain this by rewriting some equations, but what I...
  36. K

    Finding total resistance in parallel circuit

    Homework Statement This is a 3-part problem of which I have solved 1 and 2. I've included here just so you can follow the problem. A 50-watt lamp, a 20-watt, a 75 watt lamp, and a 100-watt lamp are connected in parallel to a 110-volt circuit. Calculate a) the current through each lamp; b)...
  37. M

    RLC parallel circuit; fourier components

    Homework Statement In my lab we did an experiment using an RLC parallel circuit, with the L and C in parallel. The voltage source was set at square waves. I am being asked to explain why there are frequencies, beyond the resonance, at which there is a peak voltage drop across the capacitor...
  38. P

    Electricity - Series and Parallel Circuit

    Homework Statement A 22-ohm resistor and a 33-ohm resistor are connected in series and placed across 120-V potential difference. 1. what is the equivalent resistance of the circuit? 2. what is the current in the circuit? 3. what is the voltage drop across each of resistor? 4...
  39. A

    Calculating Current Split in Parallel Circuit with Frequency of 100 sec-1

    Homework Statement A capacitor is placed parallel across a resistive load in a circuit. C= 0.829*10-6 F and R = 229 ohms. What fraction of the current goes through the capacitor when the frequency is 100 sec-1? Homework Equations I(resistor) = V/R I(capacitor) = C * (dV/dt) = ω*C*V (?)...
  40. S

    Calculating impedance for parallel circuit

    Hi there, Below shows the solution to the circuit. However i am confused about how to solve the eq in red box. http://img208.imageshack.us/img208/2797/123vv.jpg do i need to solve it by calculator or more work needs to be done? If it's by calculator i am using sharp and i couldn't get the...
  41. T

    How Do You Verify Calculations in a Parallel Circuit Problem?

    Homework Statement Here is a crappy sketch of it Homework Equations The Attempt at a Solution I have already discovered Vt=50v Rt=117.27Ω It=0.42A Pt-42v I'm not completely sure if its correct but, that's as far as i can get. The rest of it just confuses me.
  42. M

    Series and Parallel Circuit Help

    Homework Statement helllo! i am having a lot of trouble on this circuit. Each resistor is 2ohms and the total voltage is 9V. I'm having trouble trying to find the current for each resistor and the voltage for each resistor. Thank you so much for your time! Here is the url to the image that i...
  43. X

    Resistance and Power if an element is removed from parallel circuit

    Homework Statement A heater consists of heating elements connected in parallel across a power supply. A wire in one of the heating elements breaks. What happens to the total resistance of the heater? And the power output of the heater? The Attempt at a Solution Will the resistance...
  44. I

    How to find the current and equivalent resistance in a parallel circuit

    Homework Statement Three 16 ohm resistors are connected in parallel and placed across a 34 V battery. (a) What is the equivalent resistance of the parallel circuit? (b) What is the current delivered by the battery? Homework Equations (a) (1/equivalent resistance) =...
  45. S

    Parallel circuit with resonant branch

    Here's a question my mate asked me to help out with, but I'm a bit stuck, any help would be good. Apologies for not being able to show the circuit (don't know how) so I'll explain it. A parallel circuit has a supply of 1 Vrms and has 2 branches. The first branch has a single capacitor of 2.2...
  46. D

    Engineering Parallel circuit equation question

    I am starting a course in Sept in electrical installation. As it's been a while since I left full time education I thought I would buy the relevant textbook to give me a head start and get my brain into gear. My problem relates to parallel circuit calculation! Example: three resistors of...
  47. T

    Capacitance in series and parallel circuit

    [SOLVED] Capacitance in series and parallel circuit Homework Statement Determine the equivalent capacitance between A and B for the group of capacitors in the drawing. Homework Equations Cseries = 1/Cs = 1/c1 + 1/c2 + ... Cparallel = Cp = C1 + C2 + ... The Attempt at a Solution...
  48. S

    What Is the Current Distribution in a Parallel Circuit with Three Loads?

    A current of 4.80 A leaves a battery and separates into three currents running through three parallel loads. The current to the first load is 2.50 A, the current to the second load is 1.80 A, and the resistance of the third load is 108 [resistance sign here ] . calculate (a) the equivalent...
  49. E

    0 resistance wire in parallel circuit

    In question 1 b at the following site: http://ocw.mit.edu/NR/rdonlyres/Physics/8-02Electricity-and-MagnetismSpring2002/6D148C87-C69B-44B6-AECA-CB9D875E0F40/0/exam2.pdf I am having trouble with 1b. At the junction right after R1, why does the current go only up and not left when the upper path...
  50. E

    Parallel circuit with humans

    Here's an episode of brainiac, where they test how much an electric fence is shocking: http://youtube.com/watch?v=-n1pSHzdahc Now at time index 2:21 they build a parallel circuit with humans. What I wonder about is why only the first two persons get strong shocks, while the others don't. Can...
Back
Top