# Search results

1. ### Engineering Parameters of transformers: open and short-circuit tests

@gneill can you help me? please?
2. ### Engineering Parameters of transformers: open and short-circuit tests

I expected to get 27,6 mH By doing what you guys said I get to a turns ratio of 2 (dividing the voltages voltages). That means the current I2rms is 2 times current I1rms equals to 10V. That means L22 = LM/2 = 15.9 mH
3. ### Engineering Parameters of transformers: open and short-circuit tests

Thanks for your contribution but that is wrong :/ It makes me obtain a wrong value for L22
4. ### Engineering Parameters of transformers: open and short-circuit tests

Can someone help me please? :(
5. ### Engineering Parameters of transformers: open and short-circuit tests

1. Homework Statement Ok I have the following circuit and data (when the subscript is "ef" it means "rms" values): I am asked to determine the parameters of the transformer r1 L11, L22 and LM with the given experimental data. 2. Homework Equations 3. The Attempt at a Solution I had...
6. ### Dot convention inductors in series: equation confusion

1. Homework Statement So I'm really confused with mutual inductors and dot convention. If your answer is going to be a link to any website I can assure you I read them all and that only left me more confused. So here are my questions: 2. Homework Equations 3. The Attempt at a Solution ->...
7. ### Modeling a third order system

1. Homework Statement Determine the parameters of the PI controller such that two of the closed-loop poles of the transfer function Gclr(s) correspond to the poles of a second order LTI system with the following specifications: i) overshoot S% = 25%; and ii) settling time ts(5%) = 120 s. 2...
8. ### Transmission line: leakage current differential equation

Really can't anyone help me? I've been around this problem for an entire day I'm losing my mind with this, it must be a simple math trick I have no freaking idea about...
9. ### Transmission line: leakage current differential equation

1. Homework Statement I have a coaxial cable with internal conductor of radius r1 and external conductor of radii r2 and r3. The material of the conductors has a conductivity $\sigma_1$. Between the conductors there is a imperfect dielectric of conductivity $\sigma_2$. Consider the...
10. ### System of multiple conductors: image method

1. Homework Statement The following figure represent the traversal cut of a system with two cylindrical equal conductors of radius r0 length l at a distance d from one another and at the same distance h of a plane conductor (conductor zero). The dielectric that surrounds the conductors is the...
11. ### Partial capacitances of a system of conductors

Hey berkeman! Thank you for trying to help. Yes partial capacitances are a little bit different than "regular capacitances" (i.e. the capacitances that figure out on a capacitance matrix). What my book says is " An alternative method – the so-called partial capacitance scheme – consists of...
12. ### Partial capacitances of a system of conductors

1. Homework Statement I have a small question about the following problem. The figure represents the cross-section of a three-conductor system comprising a communications coaxial cable of length l running parallel to a conducting wall (reference conductor). Determine the partial capacitance...
13. ### Magnetic field of a ferromagnetic cylinder

Ok, got it! This was a very interesting problem indeed, so thank you for your recommendation.
14. ### Magnetic field of a ferromagnetic cylinder

@Charles Link as you advised me I gave a look into this problem. I have a few questions though that I hope you can help me clarify. My doubts are in the expression you use (the constant $\mu_0$). Shouldn't we use ? And ? However by doing that I get to $B= \mu_0 M$. Is that wrong?
15. ### Engineering Determine the input impedances of a circuit

Hi! Yes I considered the theoretical model given in class, that takes beta as a constant. I also noticed that the LTSPICE model of the transistor includes a finite value for the Early voltage, while in the theoretical analysis we are instructed to assume that this voltage is infinite (therefore...
16. ### Engineering Determine the input impedances of a circuit

Do you have any idea what's going wrong?
17. ### Engineering Determine the input impedances of a circuit

The fact that I obtained 240K in my theoretical analysis... It's an error of 17%, isn't this too much? I'm afraid 240k is the wrong value, but I revised my calculations and I don't see the mistake.
18. ### Engineering Determine the input impedances of a circuit

Ri2 is the INPUT impedance of the second step of amplification. Yes, RL charges the output of the circuit
19. ### Engineering Determine the input impedances of a circuit

Hi! I did a new measure considering the peak of the output voltage as the frequency to measure my resistances and obtained 19.6 k for Ri1 (which is pretty satisfactory)... But 200 kohm for Ri2! What am I doing wrong?
20. ### Engineering Determine the input impedances of a circuit

1. Homework Statement I'm studying a circuit with BJT's and I'm asked to determine the input resistances of the two amplification steps of the circuit. The circuit I'm analyzing is the following one: 2. Homework Equations 3. The Attempt at a Solution To determine the input resistances I...
21. ### Engineering Biasing circuit with a MOSFET: am I missing something

1. Homework Statement I have the following circuit with MOSFET (cascode amplifier). [![enter image description here][1]][1] [1]: https://i.stack.imgur.com/BAqQh.png Information given: $V_t=1V$ $I_1=20\mu A$ $k=10 \mu AV^{-2}$ Knowing that $V_b$ is 5V determine the minimum value...
22. ### Mosfet equation: how to get it?

Oh I got what I was doing wrong! I was assuming the current I_D was constant when taking the derivative which is obviously wrong. Thanks!
23. ### Mosfet equation: how to get it?

What do you mean? Why using the chain rule here? I'm supposed to take the derivative of I_D in relation to V_t and that's exactly what I'm taking.
24. ### Mosfet equation: how to get it?

I get $$-2k(V_G - R_SI_D-V_t)$$
25. ### Mosfet equation: how to get it?

1. Homework Statement I'm studying the following circuit with a MOSFET [![enter image description here][1]][1] [1]: https://i.stack.imgur.com/gEEdQ.png 2. Homework Equations 3. The Attempt at a Solution Now for analyzing this circuit my book came out with various equations (which I...
26. ### What does this voltmeter measure?

Hi! Oh yes that's the better approach, I didn't thought about it, thanks! The phase difference between the voltages across the inductor and the capacitor is \pi. Since the overall effective voltage is 1 that leaves us with two options: the voltage on the capacitor is zero (this is the case...
27. ### What does this voltmeter measure?

1. Homework Statement Consider the following circuit where i(t) is sinusoidal and exists across both components. (1) is an inductor and (2) is a capacitor. The ideal voltmeters measure effective value. What is the value measured by V2: [![enter image description here][1]][1] [1]...
28. ### Engineering Analysis of a servo motor

1. Homework Statement 2. Homework Equations I'm studying a mathematical behaviour of a servo motor and I need some help to understand it. The output signal is \$\beta (t)\$, representing the angle rotated by the axis at instant t, in relation to the equilibrium position. On the servomotor...
29. ### KCL with phasors: how to proceed knowing effective values

1. Homework Statement I have the following problem. Consider a circuit node where 3 sinusoidal currents with the same frequency converge, i1 i2 and i3. Knowing that the effective values of i1 and i2 are I1ef=1A and I2ef=2A. What can we say about I3ef: Options: $$(a)1A \leq I_{3ef} \leq 3A$$...
30. ### 3 resistors in parallel: how to get there

Oh I finally got it! Thank you very much !!