# Search results

1. ### Magnitude and direction of k vector

Thanks for the guidance.
2. ### Magnitude and direction of k vector

Shouldn't direction be unit vector like The vector you mentioned divided by |k|?
3. ### Magnitude and direction of k vector

To be honest this is all so maths. Thanks for this. What does 78540 signify. I mean so much radians / cm.
4. ### Magnitude and direction of k vector

I didnt understand the question. The magnitude is 2(pie)/wavelength. I get 78500 rad/cm which is pretty wrong as guess. Where would angle come into picture? Ref: https://www.millersville.edu/physics/experiments/062/index.php Shouldn't direction be like i + j + k ? So will it be like: |k|cos30...
5. ### How is this graph Hamiltonian and Eulerian?

Thanks. Guess the website has it wrong then.
6. ### How is this graph Hamiltonian and Eulerian?

Is the graph Hamilton and Eulerian? The website says the graph is Hamilton and Eulerian but I think it's wrong. Ref: https://scanftree.com/Graph-Theory/Eulerian-and-Hamiltonian-Graphs There is no path that covers all paths only once. Any help? I think the graph is drawn wrongly.
7. ### (resolved) Seebeck effect: why can't electron+hole combine at cold end?

Sorry for question. I found a more appropriate diagram: Ref:
8. ### (resolved) Seebeck effect: why can't electron+hole combine at cold end?

Hi, In seebeck effect: Ref: Once the red region is hot, the electrons and holes move toward cooler region i.e. bottom. So there is a positive potential toward right side of cold side and negative region toward left side of cold side. So why can't the electrons and holes combine here only...
9. ### Wireless Power Transfer (is this correct)

How Could you explain the working of this circuit? I found a slightly difference circuit: It says: In transmitter section, the Transistor is generating high-frequency AC current across the coil and the coil is generating a magnetic field around it. As the coil is center tapped, the two sides...
10. ### Wireless Power Transfer (is this correct)

But I drew the original circuit that I have posted in matlab simulink and was able to get oscillations. I had kept source voltage around 0.4V
11. ### Wireless Power Transfer (is this correct)

Ref: https://www.semanticscholar.org/paper/Design-and-Simulation-of-Different-Wireless-Power-Baroi-Isla m/dc19ecfde904964704777ab5adef96d5d6846f1f I couldn't find the working of this circuit so I guess it would be like: Initially transistor is OFF, so the current flows through Base, and...
12. ### How does a PLL work?

Oh boy! Electronics is super difficult. Electrical engineering is easier, to be frank, cause there at least we can visualize stuff. With electronics, it's more maths and equations :(
13. ### How does a PLL work?

Thanks for all the replies. It's very helpful. Sorry for the late reply. I had gone home for holiday. This is where I have doubt. If the difference between input and output phase is zero then the output of LPF will be zero and thus the VCO will get 0 signal in that case? Or maybe the final...
14. ### How does a PLL work?

I'm just having a hard time to understand why convert phase difference to frequency output. I mean in feedback the goal is to reduce output error. Like you run a system, and the feedback will give part of output to the input. This will be error and the final goal is to reduce error by using...
15. ### How does a PLL work?

So if the output frequency is same as input frequency why would the PLL be used? To get stable frequency as output? I read about Frequency Multiplier now though. Thanks for the answers.
16. ### How does a PLL work?

So once the output frequency matches the input frequency, will the phase detector give any output signal or will it give zero? Let's assume at some point difference between input phase and feedback phase is 30 degrees. So VCO will get a DC signal that is proportional to 30 degrees. So VCO will...
17. ### Royer Oscillator Working Principle

Thanks for this.
18. ### How does a PLL work?

From reference: https://www.elprocus.com/phase-locked-loop-operating-principle-and-applications/ It says that the PD produces an output that is DC level proportional to (Fi - Fo) (I think it has typo. It should be '-' but they've printed '+'). Then the low pass filter removes the high...
19. ### Royer Oscillator Working Principle

Lol.. Thanks again :)
20. ### Royer Oscillator Working Principle

Thanks a lot. Very helpful!!! One last question (a bit silly maybe). Why would the flux collapse? I mean in case of a capacitor once we charge it, then unless there is a closed path (preferably with a R in series) the capacitor won't discharge (assuming leakage to be 0) But in circuit that we...
21. ### Royer Oscillator Working Principle

Ok... Thanks a lot for this help. I was struggling a lot to understand how this oscillator works.
22. ### Royer Oscillator Working Principle

When you say Q1 open, you mean it's short circuit right? How do you figure out dot convention for transformer? There was this another circuit on this link: https://www.assignmentpoint.com/science/engineering/wireless-power-transmission-via-magnetic-resonant-coupling.html From link: When power...
23. ### Royer Oscillator Working Principle

Are you talking about Q1 or Q2? Suppose Q1 is initially on, so current path is Then flux across N1 will saturate and reach a constant value. So emf across it will reduce and become 0. Then what will happen? It's inductor so eventually it'll be short circuit for DC current. Why will current...
24. ### Royer Oscillator Working Principle

Once the primary current reaches maximum, why will it decrease?
25. ### Royer Oscillator Working Principle

Hi, I am studying Wireless Energy Transfer and I find Royer Oscillator in that. Ref: Wikipedia https://en.wikipedia.org/wiki/Royer_oscillator I am unable to understand how it works. I found a diagram here: Ref: https://www.smps.us/inverters.html It says that (quoted from webstie): In practice...
26. ### How does this have 24 transistors?

Then she'll ask me why I missed her class, and I was at the gym at that time.
27. ### How does this have 24 transistors?

Because I missed her class and I saw this in her video lecture. And she is in another campus. Her lectures are conducted online.
28. ### How does this have 24 transistors?

Our professor is teaching this circuit and she mentioned there are 24 transistors. But I counted and it comes out to be 22 T1 to T4 needs 2 (transistor) * 4 = 8 transistors Each inverter needs 2 transistors. so 7 inverters need 14 transistors. total 22 transistors. Unless we're also creating a...
29. ### Engineering Output waveform after input rising edge and before output falling edge

True that they are clock edges but I don't know time period of A. if A is high for 4 clock periods, then C must be high for 2 clock periods (rise one clock period after A, and fall one clock period before A). And if A is high for 7 clock periods then C is high for 5. The delaying A makes sense...
30. ### Engineering Output waveform after input rising edge and before output falling edge

How can you make the bottom waveform? How can we get the falling edge of the output, before the falling edge of the input?