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Type: Posts; User: dzafar
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2nd December 2018, 03:55
Thread: Coulomb Gauge vs. Lorenz Gauge
by dzafar Replies
 0
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 733
Closed: Coulomb Gauge vs. Lorenz Gauge
Hi there,
I am trying to solve Problem 10.5 from Griffiths Introductionto Electrodynamics. The problem says:
Which of the potentials in Ex. 10.1, Prob. 10.3, and Prob. 10.4 are in the Coulomb... 
2nd November 2018, 00:02
Thread: What is the meaning of Skin Depth?
by dzafar Replies
 1
 Views
 1,033
Closed: What is the meaning of Skin Depth?
Hello,
My book defines skin depth as "a measure of how far the wave penetrates into the conductor".
Just to double check if I am on the right track of thought, does this mean that since it is a... 
30th September 2018, 22:55
Thread: General Identity of Derivative
by dzafar Replies
 8
 Views
 2,253
[SOLVED]Closed: Re: General Identity of Derivative
Okay.. so I figured it out.
My mistake was that I was taking B directly inside the derivative and making it a B^2. The correct way is to apply the product rule for derivative. For simplicity I am... 
27th September 2018, 23:10
Thread: General Identity of Derivative
by dzafar Replies
 8
 Views
 2,253
[SOLVED]Closed: Re: General Identity of Derivative
Okay!! I know what I wrote DOES make sense. B is NOT a variable. It is a VECTOR FIELD!!!
Once you understand that it is a vector, then you would see that vector dot the same vector is equal to the... 
27th September 2018, 21:58
Thread: General Identity of Derivative
by dzafar Replies
 8
 Views
 2,253
[SOLVED]Closed: General Identity of Derivative
Hello,
I know this is really stupid BUT my mind is still questioning it. I am taking the dot product of magnetic field, B with its derivative:
B.∂B/∂t ................(i)
= ∂B2/∂t ........(ii)... 
1st August 2018, 22:51
 Replies
 11
 Views
 1,418
Closed: Re: Wein Bridge Oscillators  Diode Stabilization
Ohh!! So you mean, when the amplitude of Vo < 0.6 both diodes are OFF?

1st August 2018, 20:56
 Replies
 11
 Views
 1,418
Closed: Wein Bridge Oscillators  Diode Stabilization
Hello there,
I cam across Wien Bridge Oscillators (attached below) but am having a hard time understanding why both the diodes are OFF at low signals?
My understanding says: when signal is low... 
15th July 2018, 08:33
 Replies
 0
 Views
 334
Closed: Getting nagative width in Chebyshev Transformer
Hi there!
Objective: To design a wideband matching transformer to match a 10 Ω load to a 50 Ω transmission line at a center frequency of 1.0 GHz, matched so that Γin < 5%.
Calculate the... 
10th July 2018, 01:04
 Replies
 2
 Views
 588
[SOLVED]Closed: Specify component values for a given gain at a given frequency
Hello there,
Attached below is the question I am trying to solve.
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(a) H(s) = 2sRC  Is this correct? Does this mean the zero is at the origin? Is the '2' considered gain?
(b) I have... 
22nd June 2018, 20:21
Thread: RFID Antenna and Tags
by dzafar Replies
 1
 Views
 368
Closed: RFID Antenna and Tags
Hello there,
I am trying to put together an obstacle detection system that detects RFID tags from a minimum distance of 3 m. These tags are to be worn by employees in a warehouse and the reader... 
17th June 2018, 21:48
 Replies
 9
 Views
 1,304
[SOLVED]Closed: Re: Half Wave Rectifier when input voltage is negative
Suppose I have an LM741 op amp. What should I look in the datasheet to get that information?
dzafar 
17th June 2018, 21:06
 Replies
 9
 Views
 1,304
[SOLVED]Closed: Half Wave Rectifier when input voltage is negative
Hello,
I am new to halfwave rectifiers. Below is a screenshot from my book.
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Can someone please explain why VOL is 2V greater than VEE?
Thanks! 
12th June 2018, 18:00
Thread: Rectangular waveguide
by dzafar Replies
 1
 Views
 385
[SOLVED]Closed: Rectangular waveguide
Hi,
I am new to rectangular waveguides. In one question I am given the source freqency, relative permitivity and permeability of the dielectric material and the width and height of the rectangular... 
24th May 2018, 02:28
Thread: Transmission Line Theory Understanding
by dzafar Replies
 2
 Views
 415
[SOLVED]Closed: Transmission Line Theory Understanding
Hello all,
I am new to transmission line theory. I am reading Microwave Engineering by David M. Pozar. He mentions:
"The key difference between circuit theory and transmission line theory is... 
5th February 2018, 21:37
 Replies
 3
 Views
 2,501
Closed: Re: Rate of Return Analysis For Engineering Economics
Yes and also explain what they did so I can use it as a reference! Isn't that the point of this forum, to help?
Thanks 
5th February 2018, 19:16
 Replies
 3
 Views
 2,501
Closed: Rate of Return Analysis For Engineering Economics
Hi there,
I am confused about rate of return analysis and cash flow diagrams.
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Any help would be appreciated.
Thanks! 
19th January 2018, 03:29
 Replies
 4
 Views
 3,300
Closed: Calculating Effective Annual Interest Rate from Nominal Interest Ratte
Hi,
I am taking an engineering economics course. The questions says:
Suppose I have an effective interest rate – 10% per month,
compounded monthly, say – and I want to transform it
to an... 
15th November 2017, 06:25
 Replies
 0
 Views
 4,501
Closed: Parameterization when converting from cartesian, cylindrical or spherical
Hello there,
I am very very confused when it comes to 'parameterizing'. I do understand the physics part of the problems but getting started on my own is nearly impossible. I am attaching some... 
4th November 2017, 03:25
Thread: Curent Density inside perfect conductors
by dzafar Replies
 3
 Views
 1,336
Closed: Re: Curent Density inside perfect conductors
So you mean in the case I provided, J will have a random value? I am just concerned about this specific case when J = ∞.0!
Thanks 
3rd November 2017, 22:24
Thread: Curent Density inside perfect conductors
by dzafar Replies
 3
 Views
 1,336
Closed: Curent Density inside perfect conductors
Hi there,
I understand that conductivity σ, inside a perfect conductor approaches ∞. Also, Efield, inside as well as on the surface of PEC is 0.
Then according to Ohm's Law: J = σE what should... 
19th October 2017, 23:26
 Replies
 1
 Views
 776
Closed: MATLAB 2D Graph of Total Charge vs. Voltage
Hello,
I am new to MATLAB. I am trying to plot a 2D graph showing total charge (in pC) vs. Voltage (in V) ranging from 1 to 10V. Below is my attempt which gives an empty window.
q_tot =... 
10th October 2017, 21:54
 Replies
 9
 Views
 2,224
Closed: Re: Conversion from Cartesian to Cylindrical Coordinate System
Dear FootTea,
Thank you for your reply. I understand that because x, y, z are not constants we can not just use them directly. However, I am still having a hard time in understanding the... 
9th October 2017, 20:41
 Replies
 9
 Views
 2,224
Closed: Conversion from Cartesian to Cylindrical Coordinate System
Hello there,
I was solving problem 1.14 in Schaum's Outlines Electromagnetics (2nd Edition).
The problem states to convert a vector A from Cartesian to Cylindrical coordinates. I am attaching... 
26th August 2017, 19:49
Thread: Critical path of combinational circuit
by dzafar Replies
 12
 Views
 2,661
Closed: Re: Critical path of combinational circuit
@TrickyDicky,
In the image I attached last time, the path delay is 5ns (say each gate has a delay of 1 ns and and all inputs are sent at time 0). What I am confused about is that the 5ns delay can... 
24th August 2017, 00:57
 Replies
 2
 Views
 704
[SOLVED]Closed: Processes and concurrent signal assignments
Hello there,
I have a question regarding ARCHITECTURES in VHDL.
1. Can processes be used along with concurrent signal assignments under the same architecture?
I think yes, please let me know...
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