Circuit Definition and 1000 Threads

  1. greg_rack

    Time constant of a discharge RC circuit, capacity and charge

    So, the only thing which came to my mind in order to solve this problem was actually to write down the equations using the discharge function, being given two instants and their corresponding charges... but doing so I'm unable to find anything. Ideally, I'd say I should find the time constant...
  2. greg_rack

    Final electric potential difference in a circuit with two capacitors

    So, each capacitor must have a different potential difference, given by its capacity and charge... this would cause charge and current accordingly to flow in the circuit. But how do I determine the final potential difference, which would of course be the same for both of them? I have tried...
  3. Vossi

    Electric Circuit Differential equation help

    I'm confused at the part how 4Vc and 48 cos(60t) are deduced, that's all.
  4. Ntip

    Force on conductors during a short circuit fault

    If I have two parallel bars serving as a DC bus with a capacitor across the output and there is a short fault event, I know the peak current is limited by V/X. The instantaneous current would be a function of the time RLC time constant. How do I relate this to the force on the conductors due to...
  5. Andrei0408

    Equation Demonstration -- Comparing a pendulum's motion to an LC circuit

    I've just learned about simple harmonic motion and I've been given the following examples: The physical pendulum (for small oscillations sin(theta)~theta), with the formula (1st pic), and the LC circuit, with the formula (2nd pic). If possible, I need the demonstration for these 2 formulas...
  6. T

    Problem with this Laser diode circuit

    I have dismantled an old DVDRW drive and taken a 4-pin laser diode from it. After connecting it to two 2A batteries (red with positive, and blue with negative), the light beam is diverging, and the brightness is even dimmer than another laser diode that I got from a presentation pen. Also...
  7. Ozen

    Increasing the Battery Life of an LED Circuit

    Hello Everybody! I am new to electrical engineering and only had 1 formal intro class on the subject (albeit I did very well in it) and have found myself in a position where I need to design a circuit for a micro reflex sight I have been designing. So let me first describe how my competitors...
  8. K

    Comp Sci Need help finding the resistor size for a circuit (Ohm's law)

    I know there is a serial and parallel circuit I know R1 = 2k, R3 = 1k and i know Vout which is 1V. And i know 5V is coming from supply. I need to calculate the size of resistor R2. I can calculate : 1) IR1 = 5-1V/2000ohms = 2mA 2) UR1 = 0,002A*2000ohms=4V voltage drop on R1 How do i go on...
  9. E

    What is the voltage in a parallel circuit?

    Potentials in points E, F, A, B are equal because there is no resistance. In my opinion, losses of potential energy in the resitors R1 and R2 are not equal (potential C ≠ potential G). Then why do we say that voltage in this circuit is the same?
  10. T

    Need help with a Kirchhoff's Laws circuit problem

    I wasn't taught how to do it at A-Level in-detail, because there are no questions that expect you to use them in a circuit problem. They only need you to know what the first and second laws are in words (i.e. conservation of charge and energy). I tried looking it up on YT, but it's confusing...
  11. E

    How to calculate the resistance of a series circuit?

    Why we say that the resistance of the series curcuit is equal to the sum of the resistances of the resistors?
  12. Kaushik

    Facing issues in understanding a Purely Inductive Circuit

    Consider a purely inductive circuit with an inductor of self-inductance ##L## and sinusoidally varying AC source of peak voltage ##V_{m}##. First of all, Why is ##V_{ac} = ε_{ind}## (where ##ε_{ind}## is the back emf)? Now, at ## t=0 ##, voltage is increasing at a fast rate. Hence, due to the...
  13. R

    I Question about Grounding in this Circuit

    Click the attached file to see the figure and the book's explanation. The explanation for 27-7 (a) makes sense as the point a comes after the grounding point and before anything else. Therefore it should have a potential of zero. But, to me, 27-7 (b) doesn't make any sense. Why should the...
  14. J

    PCB Layout questions for my High Voltage circuit

    I am looking at using a few 2 kV film box capacitors in series and I'm trying to make the board as compact as reliably possible. Let's say that I have two equal valued series capacitors rated for 2 kV each in series across a 4 kV power supply. Each capacitor will then have a voltage at 2 kV...
  15. curiosissimo

    Using Kirchhoff's laws on this current division problem

    The main problem is the verse of the 2 currents ## i1 ## and ## i2 ## . I think they both go clockwise, so in the node A we should have ##i1+i2=20A##. Now let's apply the second law (going clockwise). So ##ΔV1-R1*i3 - R2*i4 + ΔV2=0##, where ##i3## and ##i4## are the currents which pass through...
  16. Anirudhhades

    LR Circuit: Answers to Common Questions

  17. A

    Are All 10 Ohm Resistors in Parallel?

  18. E

    Does the electrostatic force create current in the circuit?

    As I understand potential difference is the reason of current. Does it mean that the electrostatic force creates current?
  19. J

    Engineering Simplifying a series / parallel circuit and calculating unknown values

    Given the circuit above, I have to solve for the labelled currents, find V total and R total accordingly. 1A is flowing through the 5Ω resistor as shown. Assuming electron flow (negative terminal to positive) for circuit. The connector in the middle was somewhat confusing. Without it, this...
  20. R

    Directional actuator control circuit

    Hi there. I want to power and control a linear actuator that is considered heavy duty. I am contemplating either using an an existing control driver or building the circuitry with various components. i want to use these attractive control buttons which are led light up...
  21. ubergewehr273

    I Extraction of a particular quantum state from a quantum circuit

    Hello everyone! I'm trying to implement a quantum circuit that yields a superposition state $$\frac{1}{\sqrt{2}} (|01 \rangle + |10 \rangle)$$ I'm using parameterized gates to achieve this. I have been able to create the state $$\frac{1}{\sqrt{2}}(|01\rangle + e^{i\phi} |10 \rangle)$$ Is there...
  22. M

    Engineering Simplification of a digital circuit

    I am trying to solve this problem I have solved this myself in two different ways, but i am getting different results. Solution # 1 Solution # 2 Now to find : Please see output is different in solution#1 and solution#2. Which solution is correct ? Is there anything I am missing.
  23. K

    I AC circuit and non-conservative field

    *Please refer to the attached question file
  24. N

    Using Complex Impedances in these RLC Circuit Calculations

  25. cianfa72

    Circuit Theory - about the applicability of the substitution theorem

    Hi, I've a doubt about the applicability of the substitution theorem in circuit theory. Consider the following picture (sorry for the Italian inside it :frown: ) As far I can understand the substitution theorem can be applied to a given one-port element attached to a port (a port consists of...
  26. M

    Engineering Help understanding this asynchronous sequential circuit please

    I am finding difficulty in understanding the sequence transition graph My Book has given solution like this Question : I have marked red circle in the above table. ...book has given E but I think it should be F ...What is correct here E or F ? Here is the state diagram given in the book
  27. jisbon

    RLC Parallel Circuit: Analyzing Current & Voltage at t=0-

    These are my attempts at doing this question, and I was wondering if I am correct so far. At t= 0-, i(L) will be 0A, since the capacitor acts as a open circuit. However, I'm not sure why V(c) at t=0- will be -20V as given by the answers. Won't it be 0V? Moving on, since current in inductor and...
  28. E

    Could you check this Li-ion charging circuit?

    Can secondary cell can be described in circuit simulator?? With other symbols like capacitor. Also I wonder if there's a program that provide secondary cell(like Li-ion battery). Please help me
  29. jozefmak

    Grounding a circuit through a capacitor/parallel RC circuit

    Hi, I have two similar circuits. One of them is clear for me but I am not sure how the second one works. Let's start with the clear one: a parallel RC circuit, which is explained here: At time t = 0s there are zero volts across the resistor because the capacitor is fully uncharged. After...
  30. Kaushik

    Understanding the Phase Difference Between Voltage & Current in a Circuit

    Consider a circuit with a witch, capacitor and an AC voltage source. The sinusoidal AC voltage source is depicted in the following graph: We know that, ##Q = CV## ##\frac{dQ}{dt} = C \frac{dV}{dt}## ##i = C\frac{dV}{dt} \tag{1}## So from the graph, the voltage increases rapidly around ## t =...
  31. Samama Fahim

    Calculating the Thevenin's Resistance of a Breadboarded Circuit

    How would we calculate the Thevenin's resistance for the above circuit? The right answer for this circuit is 1.5 kOhm. $$R_{567} = R_7 + (R_5 \parallel R_6) = .5 + .67 = 1.2 k\Omega$$ $$R_{34567} = R_3 + (R_4 \parallel R_{567}) = 1 + .75 = 1.75 k\Omega$$ $$R_{TH} = R_1 + (R_2 \parallel...
  32. A

    Calculation with this electric circuit (battery and resistors)

    Hey, I am struggling a bit, als I try to solve this problem - I‘d say all five statements are correct, but it is said, that one must be incorrect
  33. T

    Another angle of "Why do you need a line 2 on a circuit?"

    I know that on an alternating current circuit, you have to have both a line 1 and a line 2 to have a circuit. Here is a pictorial diagram of an alternating current circuit: In a previous thread, I asked why would an AC circuit like in Diagram 2 not work? Here is a photograph of diagram 2...
  34. Helena Wells

    Voltage Substractor simple circuit

    I have created a voltage adder using this circuit where Va and Vb are the input voltages. And Vout is between the emitter and the resistor. How can I modify it to a voltage substractor?
  35. Kaushik

    Question about charged capacitors and inserting a dielectric into one

    First when it is connected to the battery, the capacitors start accumulating charges such that the potential difference equals that of the battery. Then the current stops flowing. ##Q_1 = CV## ##Q_2 = nCV## Where 1 and 2 represent the capacitor with capacitance C and nC respectively Then, when...
  36. M

    Engineering Calculating Power Lost in a Resistor (within Transformer Circuit)

    Hi, I have a simple question that I don't have a fundamental understanding of: do resistors dissipate reactive power (in addition to active power)? For context, when we are looking at a transformer (single phase) equivalent circuit (similar to the one in the image attached), we are asked to...
  37. E

    Help designing an electrical circuit for camper van

    Hi everyone Hopefully I am not out of line posting in this forum. I am looking for some advice planning the electrical system for my camper van. I know very little about electrical circuits and all related to it, and after 4 days of research I am still nervous to spend a lot of money and...
  38. Kaushik

    Does potential drop when a charge flows through a wire w/ 0 resistance?

    Let us connect a battery of potential difference V to a wire. There is no resistance. Nothing! Now the battery creates some potential difference and the charges in the conducting wire move due to the Electric field created in the conductor by the battery. So, as the charge moves, its potential...
  39. T

    A different angle of Why do you need a line 2 on an AC circuit?

    Preface to thread: I am darn well aware of the fact that on an AC circuit, there has to be a line 2 after the load to bring current back to the power source. This thread is about WHY does there have to be a line 2 after the load to bring current back to the power source. I hope that I don't...
  40. D

    How to calculate R1 and R2 in this RC circuit

    Using the Capacitor voltage vs. time graph, I calculated the time constant τ when the switch is closed (capacitor charging) and open (capacitor discharging). I calculated τclosed = 2.5s and τopen = 3.75s. Since the resistors are in parallel when the switch is closed, I assumed that 1/Req = 1/R1...
  41. Boltzman Oscillation

    Where is the demodulator in this AM receiver?

    I am trying my hands on building receivers and transmitters. For now I would like to build this receiver here: now I see that the 500pH inductor in parallel witht he 200uH capacitor are in charge of filtering the unwanted frequencies. The top-left NPN is in my guess an emitter follower to...
  42. Frigus

    How to simplify this capacitor circuit?

    I tried to find logic behind how do we simplified the circuit as given for 2 hours and I unable to find any clue. I can do it just by following rules but I am unable to get intuition. I tried to make sense of it but how can we even make two points as one.
  43. J

    Dr. Middlebrook's "Technical Therapy For Analog Circuit Designers"

    Dr. R. David Middlebrook was a very well known professor of analog engineering at Caltech. He was also a cofounder of the power supply design and analysis group "Teslaco". Dr. Middlebrook developed a program "Technical Therapy for Analog Circuit Designers". The dvd was available for several...
  44. Boltzman Oscillation

    What approach should be used when solving a circuit?

    I am close to graduating as an EE major but I have never been able to organize a step by step method on analyzing a circuit. It seems to me that every time I am trying to analize a circuit I end up with a bunch of equations and nothing more. I know that I should: 1. Know what I am solving for...
  45. naftacher

    Confused as to where I begin to solve this circuit branch problem

    I am thinking that this circuit needs to be simplified somehow? Finding an equivalent resistance and moving from there?
  46. naftacher

    Struggling to find the equivalent capacitance of this circuit

    I asserted C3, C4, and C5 to be in series. **I found the capacitance of "C3-4-5" to be 1.67x10-6 F. This I did by using 1/C = 1/C3 + 1/C4 + 1/C5 Then I noticed that I had another series circuit of "C3-4-5" and C1, and C2. Again, I used a similar formula. I obtained an equivalent capacitance of...
  47. Boltzman Oscillation

    Engineering How does this Bipolar RF Amplifier + Output Transformer circuit work?

    I am trying to create a receiver for a personal project I am working on. This is the RF amplifier that I was given by a book I am following. How does this circuit work? Usually for a BJT amplifier I find the DC bias point and then use the small signal model after I bias the circuit? I understand...
  48. Adesh

    Capacitors connected in series: Why is the voltage the same?

    Here is a circuit diagram: . We have three capacitors, with capacitances ##C_1##, ##C_2## and ##C_3##. Plates are labelled as ##A_1, A_2, A_3 ... A_6##. Point P is connected to the positive terminal of the battery and point N is connected to the negative terminal of the...
  49. cnh1995

    Engineering Why Does Doubling the Time Solve the AC Transient Equation in an RC Circuit?

    Here, at voltage source zero crossing, cos(2to + pi/4) =0. So, 2to+pi/4 = pi/2 This gives to=pi/8 = 0.3926s. But the given answer is twice the answer I got i.e. 0.7852s. Have I missed anything here?
  50. rachelmaddiee

    Voltage drops in a series circuit

    Known: V source = 30.0 V , R1 = 15.0 W, R2 = 15.0 W, R3 = 15.0 W To determine the current, first find the equivalent resistance. I = Vsource/R and R = RA + RB = Vsource/RA + RB 30.0 V/15.0 W + 15.0 W + 15.0 W = 1.5 A This is as far as I could do the work for this question. I’m having trouble..
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