circuits

  1. S

    Help needed with concept of electricity, magnetism and EM

    Hi, so I've just started learning about physics and I get the gist of most of it. I understand motion, torque, energy, light, radioactivity. But there is one topic that absolutely stumps me. Electricity. Can someone explain to an absolute moron like me what it is? It seems like everyone around...
  2. B

    Engineering XRLC Circuit Current Response

    1. Homework Statement FIND i(t). 2. Homework Equations VL = L*(di/dt) (Equation 1) IC = C*(dV/dt) (Equation 2) I(t) = e^-9*t*(A*cos(4.359*t) + B*sen(4.359*t)) A (Equation 3) 3. The Attempt at a Solution I can get the exact value of the constant B as shown in the answer if I use -6...
  3. S

    Will this circuit work? what am i missing?

    hi, so i want to be able to run a motor depending on whether or not an IR detector senses IR light. so the basic idea at the start was to connect the motor with the detector and a resistor in series and therefore if there is IR the current will flow turning on the motor. I then learned that the...
  4. F

    Electric Potential Energy Conversion

    Hello everyone, Imagine two points that have a Electric Potential Difference of 10V and they are connected through a conductor wire. Let's call these points A and B: Now imagine we have a charge on A of 1C. To move the charge to B, we need to make a work of 10J, right? So, now, imagine the...
  5. T

    Engineering Circuits, linear algebra

    Hi I got stuck at the following circuit problem which involves linear algebra, since I am not a physics major, I dont even have the basics to get started. Please shed some light, really appreciate it! Thanks a lot. 1. Homework Statement Consider a long chain of resistors wired up like this...
  6. C

    V-i characteristics for voltage divider with current source

    This is a problem from Foundations of Analog and Digital Electronic Circuits by Agarwal & Lang, I'm going through it by myself, I'm not in a course, so I'm depending on you friendly forum people for help! I really like this book but it has a lot of errors, perhaps this is another error. 1...
  7. R

    Change in total energy of capacitance

    1. Homework Statement When an initially charged capacitor is connected in a circuit with an uncharged capacitor, why would the total energy of both capacitors be less than the initial energy of the charged capacitor? 2. Homework Equations This was a question asking for an explanation, so I'm...
  8. C

    How do we differentiate pcb?

    they have different names or something else?
  9. A

    Basic inductors question

    A d.c circuit consists of a switch, lamp and inductor. The inductor is replaced with an inductor with twice the number of turns in the coil of wire, nothing else about it is changed. State the effect on A) maximum current B) the time to reach max current I thought increasing the turns would...
  10. T

    Thevenin and Norton equivalent circuits

    Hi guys, Sorry if all you guys think this question is too easy. But I have a hard time to understand how to group the resistor. I suppose to find the the thevenin and Norton equivalent circuit. This is what i think about the combination of resistor. Req1= RL+1k Req2= Req1 ll 3.3k (3.3k after...
  11. P

    Power dissipated by a resistor in a circuit

    1. Homework Statement 2. Homework Equations P = V^2 / R 1/Rt = sum(1/Ri) (parallel) 3. The Attempt at a Solution Since all the answer choices express the solution in terms of V^2 / R, I tried to find the voltage drop across resistor #2 to find the power. I collapsed the two parallel...
  12. I

    Voltage generators in open edges and Thevenin's generator

    1. Homework Statement I hope you can see the picture clearly. Someone drew lines over it,so please try to ignore that. The problem here is to determine the current of ideal current source Ig, if following parameters are known: -E1=50V, E3=30V -R1=200Ω, R2=500Ω, R3=3kΩ, R4= 10 kΩ -C=0.7 μF...
  13. P

    Potential difference across two points in a circuit

    1. Homework Statement Find the potential difference between points b and a in the circuit below I have already solved for the voltages of the two batteries (1 and 2) in the circuit (18 V and 7 V respectively) 2. Homework Equations Kirchhoff's Rules 1) Potential difference across any closed...
  14. I

    Engineering Calculating net change of capacitor charge in a circuit

    1. Homework Statement This problem apparently has a simple solution if you are good with circuit theorems but no matter what i try or how i combine them, it's just impossible. Given a circuit on the picture, and circuit parameters E3=12V,R1=1kΩ,R2=30Ω,R3=150Ω,R6=200Ω, if it is known that...
  15. MarcusAu314

    Basic Electronics: Transistor confusion

    So, recently I started learning about electronic components and then I started learning about semiconductors. The one which I've been having some real trouble to understand its function is the transistor. So I bought an electronics textbook called El ABC de La Electrónica (The ABC of Electronics...
  16. U

    Electrical Potential between 2 points

    Mentor note: Member warned about posting a question without the template 1. Find the electrical potential between A and B given that R1=R2=R4=100 Ohms; Power dissipated by R3 is 200 mW at 9 Volts [ code ] A---------R1-----------*------------------- | |...
  17. S

    Multiple EMFs in a circuit

    1. Homework Statement So this is not really a 'solve this problem' question, but, rather, I am trying to understand how they can call ABCDEFA a 'closed loop' even though there is another connection (BE) inside it, and why the equations work. Keeping in mind that I am still in high school...
  18. Captain1024

    Help Finding Transfer Function Vo/Vs

    1. Homework Statement Find ##a)\ H(s)=\frac{V_o}{V_s}## of the filter in the circuit below. ##b)\ ##The center frequency ##\omega_0## ##c)\ ##The band-width B Correct answers: ##a)\ H(s)=\frac{6s}{12s^2+11s+1}## ##b)\ \omega_0=0.28\frac{rad}{s}## ##c)\ B=0.71\frac{rad}{s}##...
  19. Captain1024

    Help Finding the Transfer Function H(s)=Vi(s)/Ii(s)

    1. Homework Statement Find the transfer function ##H(s)=\frac{Vi(s)}{Ii(s)}## The circuit consists of a voltage source and a 5H Inductor in series with a 10Ohm Resistor which are in parallel with a 10uF Capacitor in series with a 500Ohm Resistor. ##\rightarrow## Diagram here. 2. Homework...
  20. G

    Engineering Simple Circuit Problem (Clarification of doubts)

    1. Homework Statement 2. Homework Equations 3. The Attempt at a Solution I did a source conversion on the right-most 1A current source to get a voltage source to work with for this question. However, when I tried to work out the solution, my values seem wrong, but I don't understand...
  21. G

    Engineering Simple Circuits (Electricity)

    1. Homework Statement 2. Homework Equations ##v1 + v2 + v3 = 0## (KCL) 3. The Attempt at a Solution I don't understand why my solution is wrong. I was taught that if I were to use Node Voltage analysis, I should put nodes with voltage sources into supernodes which was what I did...
  22. A

    Normalize Angular Frequency

    Hey all, This question may sound daft, but how do I normalize angular frequency? For a little background: I'm trying to optimize some circuits, and I've managed to write some successful code using the "Design of Ultra Wideband Antenna Matching Networks" book, but the code requires normalized...
  23. H

    Voltage drop question - need check/advice

    1. Homework Statement What do you predict the voltage will be measured from B to D directly? Vtot = 1.0 V peak-peak Two parallel branches, one with two 1.5 kOhm resistors in series, one with a 1.5 kOhm resistor and a 0.1 μF capacitor in series (see attached diagram) 2. Homework Equations...
  24. G

    Finding Unknown Currents in a Two-battery Complex Circuit

    1. Homework Statement Look at the circuit given in figure 1. Solve for the three currents, I1,I2,I3. 2. Homework Equations KVL: Sum of voltages in a closed loop equals zero KCL: Sum of currents entering a junction equals the sum of currents exiting a junction Ohm's Law: V=IR NOTE: Nodal...
  25. M

    Find the resistance for maximum power transfer

    1. Homework Statement Find the value of R where RL equals 50 Ω, for maximum power transfer I= 2A, R_L=50 ohms 2. Homework Equations R_th=V_oc/I_sc KCL,KVL,V=IR 3. The Attempt at a Solution First, I created an open circuit including everything except R_L. Then i tried to solve for the Open...
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