The electrical-engineering tag has no wiki summary.
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1answer
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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 ...
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0answers
28 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 ...
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2answers
83 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.
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0answers
27 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
65 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
23 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 ...
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3answers
64 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 ...
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1answer
81 views
Differentiating a sinusoid [closed]
http://i.stack.imgur.com/ndLgm.png
I don't see the how the author derived that $\frac { dv }{ dt } \leftrightarrow\overrightarrow { V } j\omega$.
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0answers
60 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 ...
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2answers
181 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 ...
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2answers
156 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 ...
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0answers
53 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 ...
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1answer
76 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 ...
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2answers
97 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... ...
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3answers
164 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 ...
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1answer
203 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 ...
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1answer
44 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?
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1answer
243 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 ...
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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 ...
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1answer
75 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 ...
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1answer
346 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 ...
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1answer
351 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 ...
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1answer
223 views
Resistance of Light Dependent Resistor (LDR)
Is there a mathematical expression relating the resistance of Light Dependent Resistor (LDR) with light intensity?
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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 ...
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1answer
176 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 ...
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0answers
58 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, ...
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1answer
269 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 ...
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2answers
571 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 ...
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2answers
134 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 ...
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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
...
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3answers
5k 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.
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2answers
171 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
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3answers
85 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
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4answers
729 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
56 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
...
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2answers
283 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 ...
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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 ...
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2answers
942 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 ...
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4answers
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Resistor circuit that isn't parallel or series
What's the equivalent resistance in this circuit (between points A and B)?
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1answer
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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 ...
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0answers
238 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 ...
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1answer
981 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 ...
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3answers
208 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 ...
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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
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1answer
364 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 ...
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2answers
305 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.
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3answers
2k views
Calculating time for a fully charged UPS
I have a UPS of 1000 Volts connected with 2 batteries each of 150 Amp. How much time it will take to consume the whole UPS (after fully charged) when a device of 1Amp is getting electricity form that ...
4
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3answers
2k views
Why and how exactly is electric motor torque limited?
Inspired by this question and specifically this answer to it.
From my experience there's always some very specific limit to how much torque an electric motor can output. For example, an electric ...
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5answers
3k views
What would be the effective resistance of the ladder of resistors having n steps
I'm a tutor. This is a high school level problem. In high school, every one have might have solved a problem of effective resistance of a ladder of resistors having infinite steps. Now the problem is ...
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1answer
156 views
Waveforms for a given ideal inverters circuit
I have the following circuit. All the inverters are ideal CMOS.
I need to draw the waveforms for each point (A, B, D, E, Vo), given that waveform at input.
What I want to ask is if what I did so ...
