The electrical-engineering tag has no wiki summary.
2
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0answers
32 views
Completing a circuit, how is the necessary voltage determined? [migrated]
When you have some device, like a TV, why is there a necessary Voltage-or current for that matter. Whenever I see circuits, it always says to find the current from the voltage and resistance given, so ...
0
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0answers
17 views
Why is zener current preferred to be more than load current in a voltage regulator? [migrated]
In a simple Zener Voltage Regulator, such as this
Why should current passing through the zener diode(zener current) be more than the current passing through the load(load current)?
or
No such ...
2
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2answers
54 views
Thevenin equivalent of a circuit
Ok so I can't post the image of my question and my attempt at it,
so I would like to ask, if anyone knows the steps to simplifying a circuit with dependent current sources, independent voltage ...
5
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2answers
99 views
Layered CMOS structure question
I am trying to understand the workings of a CMOS image sensor. I understand that increasing wavelength results in an increased penetration depth in the silicon often used in CMOS image sensors. What ...
0
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1answer
43 views
Current in AC circuit
The problem is to find the current on the capacitor. $I''$ should be correct, but I don't know how to construct the formula for $I'$.
I managed to get the value for $I_c$ using Thevenin and Norton ...
1
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0answers
30 views
Power transfer in a transformer
Can it be proved using the concept of induced emf that power supplied at the primary coil equals power consumed at the secondary. I tried following. Let primary coil be called 1 and secondary be ...
5
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2answers
101 views
Is it viable or possible to make your own transistor?
Just wondering if it is possible/viable to construct your own transistor, not small like todays, but the same scale as the one created at Bell Labs.
0
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0answers
28 views
Differential BJT Amplifier [closed]
I am trying to solve this assignment
Consider this schematic (the BJT's are in the effective area, with
$\beta=200$ so as to $i_e\approx i_c$).
Define the common and differential gains, ...
2
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1answer
95 views
How we approach RLC circult from RLGC model?
In the text, it introduces a practical model to investigate a transmission line (like BNC cable), it considers the transmission line has resistive $R$, inductance $L$, conductance $G$ and capacitance ...
2
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1answer
26 views
Application of plasma actuators for flow control of moving objects
I've recently been to a converence on plasma physics were, to my surprise, a lot of presentations were concerned with plasma actuator.
Could someone, preferably in the field, tell me how long people ...
1
vote
3answers
75 views
When does Thevenin's theorem not apply (modelling a power source with a ohmic internal resistance)
Most physics text books say that a power source can be modelled as an EMF with a internal resistance. This is also know as Thevenin's theorem or Norton's theorem. However I have read in some sources ...
-1
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1answer
82 views
Differentiating a sinusoid [closed]
http://i.stack.imgur.com/ndLgm.png
I don't see the how the author derived that $\frac { dv }{ dt } \leftrightarrow\overrightarrow { V } j\omega$.
2
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0answers
95 views
How did the Bardeen-Brattain point-contact transistor work?
How did the Bardeen-Brattain point-contact transistor work?
What are the conditions under which a Schottky barrier injects minority carriers?
In a bipolar junction transistor the forward-biased ...
0
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2answers
208 views
How to teach myself physics needed at undergraduate electrical engineer level? [closed]
I want to learn electrical engineering on my own, specifically because I'm interested in loudspeaker design, more specifically how to design active dipole loudspeakers using DSP crossovers.
I have ...
0
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2answers
219 views
How does current flow from the emitter, through the base and to the collector in a NPN transistor?
So, I understand that for a NPN transistor to work the emitter-base junction needs to be forward biased and the collector-base junction needs to be reverse biased. I understand how current flows from ...
0
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0answers
70 views
Transfer functions of active filters
I've been looking for some straightforward method or trick to obtain the transfer functions of active filters (like the Sallen-Key filter, the butterworth or Cauer topology etc...) since KCL or KVL ...
0
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1answer
85 views
Full wave rectification [duplicate]
In the construction of a full wave rectifier, why is there central tapping in the secondary winding of the power transformer? What's the pure reason behind it? If there was no central tapping, what ...
2
votes
2answers
112 views
Electronic filter
Can you explain, please, step-by-step how Electronic filter does work?
For example, high pass filter. I know It's a trivial things, but I can't get it completely. Don't bring me formula and etc... ...
3
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3answers
186 views
Why is electrical energy so difficult to store?
Does anyone know a general answer to these questions? (I've asked them together because they're all pretty related, it seems.)
Why is it that we find electrical energy so difficult to store? Do we ...
0
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1answer
340 views
What is the role of center-tapping in a full wave rectifier?
Note: I have already tried googling. Although similar questions have been asked on different forums, I couldn't find a detailed explanation, which I could really understand.
Circuit diagram ...
1
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1answer
53 views
Why is spectral sensivity of a photodiode expressed in A/W
Can someone explain me the meaning of the A/W unit of the photosensivity when reading a spectral response function of the wavelength characteristic of a photodiode?
0
votes
1answer
271 views
AC Circuit Theory Maximum Power Transfer
I am currently hitting a barrier with regards to the basics of this question.
A 50HZ supply is connected to various given impedance's, calculate the maximum power transfer.
Maximum power transfer I ...
0
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0answers
36 views
How can a force be applied on hole? [duplicate]
What is actually a hole? Actually that is not a particle, but books are explaining that in semiconductors the polarity of Hall effect depends on the type of charge carriers whether it is p type or n ...
1
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1answer
77 views
Instrumentation handbook [closed]
Does anyone have any suggestion on a handbook of instrumentation?
In particular NIM instrumentation...
I would like an approach which will explain the techniques and how to use NIM modules.
In ...
0
votes
1answer
386 views
PN Junction Depletion Region
So it took me a little bit to understand this, but I want to make sure I have a few things right.
First of all, when a Crystal Structure with One side N-Doped, One Side P-Doped are in the same ...
0
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1answer
390 views
Explanation for transistor as amplifier
In transistor as an amplifier, we have NPN transistor (base in the middle and emitter and collector at the sides). The collector has electrons in majority because it is N-type. similarly, holes are in ...
1
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1answer
236 views
Resistance of Light Dependent Resistor (LDR)
Is there a mathematical expression relating the resistance of Light Dependent Resistor (LDR) with light intensity?
0
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0answers
19 views
How are current and voltage out of phase in capacitive circuit? [duplicate]
Possible Duplicate:
Physical explanation for capacitive circuit
We say that in capacitive circuit, the voltage and current are out of phase. Current is 90 (degrees) ahead of voltage. What ...
3
votes
1answer
192 views
Explanation of the Graetz circuit
My knowledge of circuits is pretty rudimentary and I've never really understood circuits, so I'm having trouble with the concept of Graetz circuits:
When you register the voltage on the resistor R ...
0
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0answers
64 views
Explanation of NMOS processes
So, gate (poly-si + $SiO_2$) and $p^{-}$ silicon operate as capacitator.
But how are voltages and charges are applied? In order for inversion to occur, there should be charges formed in poly-Si, ...
0
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1answer
317 views
Capacitance per unit area and CMOS case
In a modern 0.35μm CMOS processor, the gate oxide thickness is around 80Å = 8nm. This gives us a capacitance per unit area of $430nF/cm^2$
I am not getting how one gets this capacitance per unit ...
0
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2answers
671 views
Current through the reverse biased junction in transistor
A transistor is a three terminal device. One terminal is called emitter, one collector and in between them is base. Now, during biasing the junction between emitter and base is made forward biased and ...
1
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2answers
142 views
How does an electrical field really work?
A little bit of background information: I'm planning to write a little booklet or web page about CPU/computer architecture, basically for my own education, because we didn't cover it in depth in ...
8
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2answers
2k views
Why is Near Field Communication (NFC) range limited to about 20cm?
Near Field Communication (NFC) operates at 13.56 MHz.
Near Field is the region situated at a distance r << λ
λ = c/f
...
5
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3answers
6k views
Why do we use Root Mean Square (RMS) values when talking about AC voltage
What makes it a good idea to use RMS rather than peak values of current and voltage when we talk about or compute with AC signals.
1
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2answers
179 views
Nodal Analysis of an electrical circuit
I have several doubts about solving circuits.
Can any circuit be solved using Nodal Analysis?
If some circuit can be solved using Nodal Analysis, can it be solved using Mesh Analysis too?
Why do we ...
3
votes
3answers
86 views
whether electricity that comes in our home comes directly after generated or first stored and then distributed
Please give answer that, whether electricity in our home comes directly after it is generated e.g. at a dam or nuclear plant or first it is stored somewhere and then distributed as it is needed.
4
votes
4answers
910 views
Do resistor-based fan regulators save no power at all?
I have heard that the traditional resistor-based fan speed regulators are inefficient. In fact, I have noticed that such regulators tend to get hot when the fan is set to low speed. However, does that ...
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0answers
57 views
Should we expect reliable nano-particle engines within the next 5 years?
"Regarding engines" what are the current theories and examples of ongoing progress in nanoparticles?
References:
National Nanotechnology Initiative
electric motor made from one molecule 18 atoms
...
2
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2answers
290 views
Lorentz engine to run a car?
Could a Lorentz engine (like the ones that move the write head inside of hardrives) be used to run car ? Would it be possable to get it producing 60hp, and a decent amount of tourque, if so how large ...
-1
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2answers
2k views
How do I calculate output voltage from a given supply voltage and resistance?
I have searched everywhere but I can't seem to find out how I can calculate the output voltage (or voltage over a component) from the resistance of a resistor (or other component) and the supply ...
4
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2answers
969 views
Strategies against 50 Hz mains hum on detector signals?
I'm having problems with a strong 50 Hz mains hum on signals created by photodetectors. I assume that they are due to ground loops and I realize that the best option would be to remove those. What are ...
5
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4answers
2k views
Resistor circuit that isn't parallel or series
What's the equivalent resistance in this circuit (between points A and B)?
-2
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1answer
211 views
what is the proper way to connect two light bulbs in a circuit? in series or parallel?
What is the proper way to connect two light bulbs in a circuit? in series or in parallel and why?
My thought is that it's better to hook them in parallel, since if we take into account Ohm's Law, the ...
3
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0answers
257 views
Turn-on delay time for Laser diode
Do you know any simple explanation on the reason why the turn-on delay time on a laser diode is reducing while we increase the bias current?
Turn on delay,is the time that the laser needs from the ...
1
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1answer
992 views
How to calculate the charge and the potential across a charged capacitor charging an uncharged capacitor?
Initially, there is a single capacitor $A$ attached to a power source that charges it to a certain voltage $V$. Once it is charged, it is instantaneously removed and placed in a circuit with an ...
1
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3answers
215 views
Intensity distribution of a LED light source
The light source: 190 high power LEDs in NIR.
I have the datasheet of the LED.
I want to make a graph showing the spatial distribution, and to measure the intensity of the beam on the whole field of ...
1
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0answers
76 views
Simplifying a biquadratic filter equation [closed]
I am trying to calculate input impedance of a multiple feedback low pass filter. What I need is the symbolic expression as simple as possible so that later I fill in the values and get the impedance ...
2
votes
1answer
372 views
Electrical flow in a simple parallel circuit
I'm having trouble understanding something in one of my text books:
Let’s have a look at the implications of each circuit configuration.
Figure 3.13 shows the Conventional representation of a ...
3
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2answers
318 views
The role of resistor in e.g. an AND gate
What is the role of the resistor in e.g. an AND gate like this one? :
One often sees lots of resistors in electric circuits, but I haven't really understood their role.
