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0
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1answer
134 views

Magnetic core, and a DC solenoid

A DC solenoid creates a magnetic field B. A highly permeability magnetic core is added to solenoid to increase B. Now, there is change in flux, due to the increase in magnetic field. What would be ...
-5
votes
1answer
153 views

traditional transformer design improvement [closed]

The traditional tranformers suffer a lot of losses in various forms, some of them are as follows : 1. Flux leakage 2. Eddy currents 3. Hysteresis Figure : But as we are taught induction we come ...
0
votes
1answer
478 views

Conservation of energy and ohms law in a step up transformer

In an ideal step up transformer with a constant resistance attached to the secondary coil, how is energy conserved and ohms law followed at the same time? $$\frac{V_p}{V_s}=\frac{N_p}{N_s}=\frac ...
0
votes
1answer
56 views

How to produce a bigger rotational velocity from two rotational velocities?

If I have two electronic motors, both running at the same voltage and current, delivering the same rotational velocity, how could I produce a bigger rotational velocity from them?
1
vote
0answers
452 views

Help making a solenoid engine [closed]

I am currently working on a school project and my aim is to build an electric motor using DC. I am looking at a design similar to this: Solenoid Engine and I have built majority of it however I am ...
1
vote
1answer
219 views

Do bifacial solar panels operate at lower temperature than normal solar panels?

Bifacial solar panels have a glass backplane instead of the usual aluminum and are designed to absorb and convert to electricity light incident on either face. Many manufacturers claim that their ...
1
vote
3answers
801 views

Would connecting p-type and n-type semiconductors work as a diode?

If we placed p-type and n-type semiconductors close enough to be touching (see fig. 1), would this arrangement work as a diode? ...
1
vote
4answers
3k views

Transformer: primary side & secondary side current 180 degree out of phase

I am a novice in electrical engineering. I notice that in transformer the secondary side current & current referred to as primary are 180 degree out of phase from each other. But why it is so, I ...
5
votes
1answer
392 views

How do High Electron Mobility Transistors (HEMT) work?

I am studying High Electron Mobility Transistors (HEMT), but I simply cannot understand how they work in the way described by the references I've read on the Internet. This is what I understand so ...
2
votes
2answers
248 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
votes
2answers
132 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
votes
1answer
85 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
vote
3answers
367 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 ...
8
votes
2answers
3k 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.
2
votes
1answer
573 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
votes
1answer
168 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
4answers
2k 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
votes
1answer
89 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
votes
0answers
671 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
votes
2answers
757 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
votes
2answers
5k 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
votes
0answers
139 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
votes
1answer
178 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 ...
1
vote
3answers
224 views

Electronic filter

Can you explain, please, step-by-step how an 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. ...
7
votes
5answers
4k 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
votes
1answer
13k 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
vote
1answer
128 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
608 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 ...
1
vote
1answer
96 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
2k 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
votes
1answer
639 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
vote
1answer
557 views

Resistance of Light Dependent Resistor (LDR)

Is there a mathematical expression relating the resistance of Light Dependent Resistor (LDR) with light intensity?
0
votes
0answers
21 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
458 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 ...
1
vote
2answers
322 views

Explanation of NMOS processes

Gate (poly-Si + $SiO_2$) and $p^{-}$ silicon operate as capacitors. But how are voltages and charges applied? In order for inversion to occur, there should be charges formed in poly-Si, right? How ...
0
votes
1answer
2k 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
votes
5answers
4k views

Current through the reverse biased junction in transistor [closed]

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
vote
2answers
503 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 ...
11
votes
2answers
12k 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 ...
7
votes
3answers
45k 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
298 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
136 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
3k 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 ...
2
votes
2answers
393 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 ...
0
votes
2answers
9k 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
votes
2answers
2k 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 ...
7
votes
4answers
5k views

Resistor circuit that isn't parallel or series

What's the equivalent resistance in this circuit (between points A and B)?
-2
votes
1answer
409 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 ...
4
votes
1answer
592 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
vote
1answer
1k 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 ...