Circuits Definition and 1000 Threads

  1. S

    I Understanding Combined Circuits: Exploring Total Current and Measured Values

    I am doing a lab experiment with regard to combined circuits, and I wanted to check my data to see if I made an error in my experiment. Theoretically speaking, in a combined circuit, should Itotal (total current) be equivalent to the Imeasured value? I calculated my Itotal to be .0292A since...
  2. T

    Confused about solving RC circuits with nodal analysis

    Problem is in the picture below. The problem is already solved, but I am confused as to why C(dv/dt) is positive and not negative, since the current is coming out of the capacitor and towards the point v(t), which is not away from v(t) like the solution shows. But if I solve the problem with...
  3. G

    Calculating Charge on a Capacitor in a Circuit with a Switch

    For the circuit shown in the figure, the switch S is suddenly closed with the capacitor uncharged. After one time constant, the charge on the capacitor is closest to: a) 2.0 mC b) 0.74 mC c) 1.0 mC d) 1.3 mC e) 0.00 mCRelevant Formulas q = Q⋅(1-e-τ/R⋅C) τ = RC My Attempt q = Q(1-e-τ/T) q =...
  4. Marcin H

    Max Collector Current in Transistor Circuits

    Homework Statement Calculate the max collector current. Homework Equations Ic=BIb V=IR The Attempt at a Solution I'm not sure how to find the max collector current. Don't I need the source voltage to find my Ib and then use that to find my Ic? Is there another way of finding Ic_max? Also...
  5. A

    Engineering Solve 2 Loop RC Circuit: Find Q(topen)

    1. Situation and Variables: A circuit is constructed with four resistors, one capacitor, one battery and a switch as shown. The values for the resistors are: R1 = R2 = 30 Ω, R3 = 66 Ω and R4 = 113 Ω. The capacitance is C = 64 μF and the battery voltage is V = 12 V. The positive terminal of the...
  6. K

    How to determine the sign of currents in complex circuits?

    Homework Statement A combination circuit powered by a 6.0 V battery is shown. What is the total current through this circuit? I don't know how to determine where the signs go, for example if the right side of a resistor is positive or the left side is positive Homework Equations What is the...
  7. S

    Electric Discharge acts as in LC Circuits?

    For the most part, do electric discharges behave as tank circuits? For example, an air capacitor; when the electric field causes the air to breakdown and conduct, will the discharge alternate at a frequency defined by the inductance of the plasma channel and the capacitance of the capacitor?
  8. Adrian Silaghi

    System Engineer: Physics & Math for Electronics/Electromechanical/Computer

    Hello I just want to know as an System Engineer student in my second year(I have 4 years in total) what kind of physics and mathematics will I use if going to work in a field let's say ( Electronic System or Electromechanical Systems or Computer). Thank you, Adrian
  9. V

    How Do Charges and Voltages Distribute in a Circuit with Multiple Capacitors?

    Homework Statement A potential difference of V = 38.0 V is applied across a circuit with capacitances C1 = 4F, C2 = 5F, and C3= 2F, as shown in the figure. What is the magnitude and sign of q3l, the charge on the left plate of C3 (marked by point A)? What is the electric potential difference...
  10. R

    Engineering How Do You Calculate V_D in Terms of Circuit Components and Constants?

    Homework Statement Trying to come up with an equation of V_D in terms R_S, R_d, R_D, V_i, G G is a constant Homework Equations Sum of voltages around a loop = 0 Sum of currents at a node = 0 Voltage divider Current divider Resistance of resistors in parallel The Attempt at a Solution...
  11. T

    What's the reason for modifying these amplifier circuits?

    If I have a bjt amplifier with pure differential input signals like this: Now let's say I apply pure common mode signals to the same circuit, then why is the circuit above modified to this ? Also when finding the Common Mode Input Resistance the circuit above excludes RE and includes ro...
  12. 5

    The sign of the current and voltage

    I was doing the following problem: And I was asked to find Iy. I found Iy to be 2.64 using KCL. However, the right answer was negative 2.64. Is it negative only because there is a dependant voltage source with "+ -" ? And why must it be negative? Does "-" in the final answer play a...
  13. Marcin H

    RL circuits: Find the voltage through the resistors

    Homework Statement Find the voltage through the resistors. Homework Equations V=IR P=IVThe Attempt at a Solution Am I doing these correctly? Can I find the voltage across the inductor the way I did it?
  14. Sam19KY

    Question about electric circuits ?

    If the current is 0.5 A and the battery supplies 6 joules of energy to each coulomb then will it supply only 3 joules per half coulomb ?
  15. Phy_TR

    Question regarding Energy in Circuits with Capacitors

    Hey everyone! I have a doubt that relates to energy stored in different capacitors (when they're in a circuit). I understand how in capacitors connected in parallel, the capacitor with the biggest capacitance stores the most energy because: E = 1/2 CV2 So naturally the bigger the capacitance...
  16. Domenico94

    What are the limitations of using electrical circuits to solve PDEs?

    Hi everyone. In electrical engineering, when you study control theory, you're taught that electrical circuits can be used to simulate the behaviour of complex systems. What I don't understand is, what are the limitation of this sistem, and why it can't be obviouslly used in a general way to...
  17. C0balt

    Understanding Electrical Circuits and Power: Questions 10&11

    Homework Statement Questions 10&11 in pictures. Homework Equations P=IV W=VIt W=Pt The Attempt at a Solution For 10a) P=IV P=70*14= 980W. 10b) P=IV 1500=12*I I=125A (which is massive so probably wrong) 10c)P=IV 60=I*12 I=5A The 8A fuse because the current flowing through each headlamp should...
  18. J

    Engineering Electrical Circuits Reactive Networks Question

    Homework Statement Homework Equations At low voltage frequency (inductors) L become short circuit and (capacitors) C becomes open circuit At high voltage frequency (inductors) L become open circuit and (capacitors) C becomes short circuit The Attempt at a Solution Part A At low frequency...
  19. F

    Engineering Electrical Engineering - circuits - Reactive Networks

    1. Homework Statement There are multiple parts to this question, but I have only got through the first 2 before getting stuck. Please could somebody give me a hand as I am really struggling :frown: (a) Calculate the phasor voltage of the voltage source and the phasor current of the current...
  20. Metals

    Why are relays used in circuits?

    I'm honestly just not getting this. What is the purpose of a relay in a circuit? What I understand so far is, a lower current somehow activates a larger one. I know how they work and their parts, but I'm not so sure on their purpose. How does a small current all of a sudden activate a larger...
  21. vetgirl1990

    Why is the Junction Rule not applying in my circuit?

    Homework Statement In my lab today, I created a circuit with resistor (R1) in series with a set of resistors in parallel (R2//R3). Using an ammeter, I measured: I1 = 2.30mA I2 = 1.25mA I3 = 0.38mA Homework Equations Junction Rule: ΣI = 0 The Attempt at a Solution So applying the Junction...
  22. Y

    Do we get 2x the frequency when doing P=VI for AC Circuits?

    I know that when you get a current from a voltage (like calculating current through resistor), the current and voltage equations have the same frequency. Does this still hold for power P = VI ? So assume V in Euler form, V(t) = Vcos(wt+theta) + jVsin(wt+theta) = V*ej(wt+theta) and in Phasor...
  23. A

    Find the resistance of a resistor using Ohm's Law?

    Hi, I have been at this problem for days and I can't seem to see what I am doing wrong. Here is the circuit layout along with my work As you can see I am running into problem getting values of current that do not add up equal to zero. My professor has never discussed how adding a wire like...
  24. Kurtis McIntosh

    Engineering Circuits Question -- Charging a car battery in 4 hours....

    Homework Statement A constant current of 3A for 4 hours is required to charge an automotive battery. If the terminal voltage is 10 + 1/2 t V, where t is in hours, (a) how much charge is transported as a result of the charging? (b) how much energy is expended? (c) how much does the charging...
  25. Z

    De facto standard file format for electronic circuits

    What's the most common way to store electronic circuits in digital form ? What is the ".pdf document" equivalent for the electronic world ?
  26. Donello

    Recommend me a Book for Circuits I ?

    Hi,The recommended book by our electrical engineering department for Circuits I is : Linear and Nonlinear Circuits ¹st Edition by Leon O . Chua /ISBN-13: 978-0070108981/What do you think are some different books about Circuits I ?
  27. E

    Exploring the Diversity of Natural Electrical Circuits: A Scientific Perspective

    Hello everyone, I have a strange question. Can complete electrical circuits be found in nature? If so, can you give any examples? And what is necessarily required (besides electricity) for a complete electrical circuit to occur, naturally or unnaturally?
  28. Donello

    Preparing for Circuits by myself and need some guidance?

    Hi,The curriculum for Electrical Engineering at the school where I am going to be studying is the following: (for 1st semester) Calculus I Digitaltechnik (Digital Technology) Linear Algebra Physics for Electrical engineering Circuit Technology ICurrently I am studying a Pre-Calculus book and...
  29. E

    Difference between RC and CR circuits

    What would be the difference in measuring voltage across the resistor in this position and when resistor and capacitors positions are in different order? And why? http://people.sinclair.edu/nickreeder/eet1150/PageArt/RCcircuitSimple.gif
  30. I

    Engineering What is the voltage on capacitance C2 immediately after commutation in circuits?

    Homework Statement By the time t = 0, the network was in steady state. At time t = 0, the switch is turned on. Find the voltage on the capacitance C2 immediately after the commutation.[/B]Homework Equations KCL i(-0) = -ic1(+0) - ic2(+0) KVL E-i(-0) * R-Vc1(-0) = 0 Vc1(+0) = Vc2(+0)...
  31. P

    Understanding Power in Parallel Circuits: V^2/R vs. i^2R

    Homework Statement Why in a circuit in parallel I can't use P= i^2 R where R is the equivalent resistance? Why do I have to use P= V^2/R ? Homework Equations P= Vi , P= V^2/R , P= i^2R[/B]The Attempt at a Solution
  32. Gbox

    Intro Physics Electric Circuit Analysis: RC Circuits

    Hi I am looking for a book with questions and solutions on electric circuit analysis, currently on RC circuit. Thanks
  33. T

    Connecting two circuits with a single conductor

    If you have two independent circuits, and then connect them at two points that are at arbitrary voltages by a single conductor, what happens to the system? A moment after the connection happens, I would assume there to be no current between the circuits since the two circuits would try and...
  34. B

    Impedances of R, L, C, RL, RC, LC and RLC circuits

    Homework Statement In first place, ignore the source in each circuit, ignore if make sense or not. I placed one sorce in each circuit just for the circuit be more visible. In second place, ignore the numerical values of the sources, resistors, capacitors and inductors. Think R, L and C in...
  35. J

    Engineering Square of resistors within a circuit. What is the equivalent

    Homework Statement Homework Equations -We can re-arrange circuit components into simpler orientations as long as the components' connections to previous nodes are maintained. The Attempt at a Solution -I attempted to re-arrange the loop of three resistors at the upper left region to no...
  36. D

    Engineering How Do You Calculate Thevenin Voltage Using Superposition?

    Homework Statement http://puu.sh/lQPvh/d0efa216ff.png Homework EquationsThe Attempt at a Solution http://puu.sh/lQPAR/2456db4783.jpg http://puu.sh/lQPCJ/f142c25f63.jpg http://puu.sh/lQPER/5eb4af107e.jpg Is this correct? I used principle of superposition to calculate the Thevenin...
  37. J

    Engineering [Intro Circuits] Simple problem, finding initial

    Homework Statement Two independent sources are given. They are active at different times. Find the conditions at t = 0- DCSS (aka t < 0 DCSS) and t = ∞ DCSS for IL and Vc Homework Equations At DCSS, replace inductor with short circuit At DCSS, replace capacitor with open circuit The...
  38. Weightofananvil

    Engineering Magnetic circuits with air coil question

    Homework Statement a magnetic circuit with a coil of 500 turns and a core of sheet steel has an air gap of 1mm. the sheet steel has a mean path length Lss = 0.25 m and a cross section that measures 1cm x 1.6 cm. (assume: u air = u0(not) = 4pi x 10^-7 wb/(Am). determine how much coil current is...
  39. K

    Amperage the same in Series Circuits?

    If current is always the same in a series circuit then how is a transformer able to make the current smaller when it increases the voltage? is this just an exception since with the voltage being higher the same amount of power is being provided?
  40. Z

    How do you calculate the total resistance?

    Homework Statement What is the Total resistance in Question 38. Homework EquationsThe Attempt at a Solution I tried drawing the circuit again splitting up the series and parallel but i got the wrong answer. The answer is 92. Like i know that the 60 is parallen to 15 and the 15 is parallel to...
  41. M

    How Six 2V lamps could be lit to their normal brightness.

    Homework Statement [/B] Homework EquationsThe Attempt at a Solution I'm not really sure how to attempt this question tbh. In order for the lamps to have normal brightness I think the circuit must be parallel. I also think maybe for A there can only be one lamp per branch because there's...
  42. J

    Circuit analysis -- Voltage question

    hello, i have a question regarding the way we represent information on circuit diagrams. The first is to do with representing output voltages: is V out always simply representing the voltage of whatever lies between/trapped between those two horizontal lines? Also, i see a lot of diagrams...
  43. jdawg

    Engineering DC Steady State Circuit Analysis: Solving for iL, i, and Vc in a Simple Circuit

    Homework Statement DC steady state circuit analysis: Consider the circuit shown below. The switch shown in the problem opens at time t = 0 seconds. If the circuit is in DC steady state at , find values for iL(0-), iL(0+), i(0-), i+, Vc(0-), Vc(0+). There is no RL or RC analysis to be performed...
  44. R

    Engineering Circuits w/ Diodes: Understanding Magnitude & Frequency

    http://imgur.com/9Yhwya0 So for #1, would I approach this problem by first considering the positive power applied to the top, making the diode on the right opened, and thus vouput being 4volts. Then for the next part would the diode on the left be in reverse bias, thus opened, and the voutput...
  45. neduet

    Why Use Concentric PE Cables in Frequency Converter Circuits?

    A cable with concentric PE conductor must be used with frequency converter circuits what does its means.?
  46. D

    How to design discrete circuits for transistor beta changes?

    In my circuits/active devices course we had to make amplifier designs with various type of transistors (BJT, JFET, MOSFET). In each design the transistor beta parameter played an important role in deciding which resistors to use in the final amplifier circuit. This beta parameter changes widely...
  47. C

    How to Calculate Equivalent Resistance and Current in a Simple Circuit Problem?

    Homework Statement Assume the electric potential is zero at the negative terminal of the battery. Calculate: a). the equivalent resistance of the circuit b). the electric potential at position a c). the magnitude and direction of the current through each resistor Homework EquationsThe...
  48. M

    How correct are these concepts about circuits?

    first of all sorry for bad drawing, is all of the following correct : * number 1 : the current will flow normally * number 2 : the voltage source will not give current but Vb-Va = V of the voltage source (10 for example) * number 3 : no current will flow * number 4 : the voltage source will be...
  49. R

    Engineering How Do You Calculate Instantaneous Power in a Resistor with Switching Circuits?

    Homework Statement Given the following switch positions in time, sketch a graph of the instantaneous power dissipated in the 50 ohm resistor with time. Homework Equations P=I^2R=V^2/R=IV The Attempt at a Solution Basically I treated the inductor as a short circuit and obtained the...
  50. Fededevi

    Magnetic circuits and Magnetization

    From my little understanding of magnetism and the magnetization process, in order to magnetize a magnet it is better to have a closed magnetic circuit. But how does an air gap affects the magnetization "strength"?Example: Assume that we have a unmagnetized horsehoe magnet with a coil around it...
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