Questions tagged [physics]

Physics is the natural science that involves the study of matter and its motion through space and time.

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GaN Vs IGBT performances

I was making some research on GaN and I do not understand why GaN is so reveolutionnary. When I take a look on the following specification RdsOn and Coss (Cds + Cgd), the GaN semiconductor has lower ...
Jess's user avatar
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Physics diagram to electrical schematic

After waiting a reasonable amount of time with no answer here, I have duplicated this question at Physics Stack Exchange. I am asking this question on behalf of user furious.neutrino. This question ...
Math Keeps Me Busy's user avatar
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Why do we use silicon in the crystal direction [1 0 0]?

In MOSFET, we use silicon in crystal direction [1 0 0] , while we use direction [1 1 1] in BJT. What is the reason? I expect the opposite, because we see more atoms on the surface in the direction [1 ...
mohammad rezza's user avatar
2 votes
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160 views

MOSFET gate substrate voltage

In a MOSFET the channel is formed between gate and the body it would sense to use gate body voltage to form the channel. Why is gate source voltage used to form the channel?
mahmoud esmail's user avatar
2 votes
3 answers
132 views

Is there a way to experimentally separate the effects of gate voltage?

I'm currently doing experiments on new kind of semiconductors. These devices have a body (source, drain) and a top gate. These devices show a response to gate voltage. The conductance changes with ...
Qwwerty's user avatar
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Factors affecting the \$V_f\$ of a Schottky diode

The usual wisdom about Schottky diodes is that their \$V_f\$ is around 0.2 to 0.3 volts, but what specifically determines this? I know that for p-n diodes, doping concentration can affect the forward ...
Hearth's user avatar
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Capacitance among N conductors

I would like to have a rough estimate of the capacitance per unit length of a system composed by N parallel identical straight wires. I tried to sketch the capacitance network but I'm able to solve it ...
Andrea's user avatar
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1 answer
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What would be the effects of a -1000 nanotesla geomagnetic storm be on modern electronics?

After reading the Wikipedia article on geomagnetic storms, I'm curious about what the effects of a -1000-nanotesla-minimum geomagnetic storm would be on modern military and consumer electronics, as ...
KEY_ABRADE's user avatar
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How does a boogie board/LCD writing tablet/ChLCD reset actually work?

there are those boogie boards, which essentially are just special LCD screens: ChLCD screens. which work by reflecting light on the places where it is activated. in a boogie board, the pressure causes ...
TeD van Loon's user avatar
1 vote
1 answer
86 views

Confusion about why pn junction discussion insensitive to doping variations faster than Debye length

Sze (Physics of Semiconductor Devices, 3e) gives the following discussion which relates to how equilibrium electric fields/equilibrium potential build-up at thermal equilibrium are related to doping ...
EE18's user avatar
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Thermodynamics of a simple electrical conductor

I derived an expression for the time constant of the temperature of an electrical conductor and was looking for some constructive feedback. Initially there is no current flowing through the conductor ...
user50655's user avatar
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Igniting and maintaining plasma in low pressure chamber

I'm trying to create and maintain plasma inside a vacuum chamber (up to 50 Pa), I have a home-made feedthrough done with an HV BNC sealed with Viton gaskets on a KF50 flange (makes a ≈25 mm gap). I ...
lasb3tas's user avatar
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Calculating steady-state temperature for electrically heated wire

I am working on a program aimed at finding optimal parameters (voltages and feed rates) for a hot wire foam cutter. One starting problem that has to be solved before even attempting to evaluate heat ...
Daniel Stepanoff's user avatar
1 vote
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301 views

How to calculate total power required for an electric vehicle (ebike) design?

I wanted to design an ebike with good enough specs to satisfy my requirements, my first consideration was the power required to move the bike at my required speed and from there I can choose a motor. ...
AhmedH2O's user avatar
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Is it possible to force charges into one plate of a capacitor?

As we know, a capacitor stores energy, but the net amount of charge in it doesn't change. If an electron enters one plate, another leaves the other plate. If the other plate is floating, the entering ...
Bart van Heukelom's user avatar
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198 views

What is this linear encoder from a old inkjet printer using a thin metal rod and a metallized glass plate?

What is the working principle of this sensor ? It was found in a canon inkjet printer from around 2000-2005. Not a fancy model, though. The metal rod broke, as it is surprisingly fragile. It doesn't ...
Howie1337's user avatar
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64 views

Solutions to wave equations

In the following steps for a solution to the Telegrapher's equations, I don't understand how equation 9.17 follows from 9.16. Substituting in \$\gamma\$ as given, it seems that the result should be \$...
Halleff's user avatar
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1 answer
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Confusion on Voltage levels in Digital Waveforms

My question is why Io is in different direction when Vo=H and Vo=L respectively? I really can not understand the underlying mechanism!
PRITAM the cat of Newton's user avatar
1 vote
2 answers
133 views

Transformer Secondary Discontinuity

I am using a step up transformer and I am getting a weird discontinuity in the secondary output. Has anyone seen anything like this before? I cant figure out what might cause this. In a one test setup ...
Marlowe's user avatar
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Realistic channel noise patterns

I'm setting up a playful coding challenge for our programmers. It's about coding theory. There are source, channel and sink. The task will be to implement an encoder for the source and a decoder for ...
schmijos's user avatar
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Repurposing or obtaining a cheap audio signal amplifier for school physics lab

I teach highschool physics, and want to connect my smartphone (LG V20) to a Chladni plate (vibrating plate for studying interference patterns in sound in solids). I have successfully done this by ...
cosmogoblin's user avatar
1 vote
0 answers
436 views

Aluminium foil not blocking IR signal

I am using an IR sensor (vishay tsop32 series) but I want to ensure that it only sender directly ahead so I made blinders out of pla and covered them in aluminium foil. However it seems that despite ...
Noam Yo Tom's user avatar
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0 answers
230 views

Peltier Module constant time and thermal Load

Hi everyone I am new to this forum. I am doing a project where I need to control one of the sides temperature of a Peltier device against human skin. So one side is in contact with the skin, and the ...
Fabian Cerda's user avatar
1 vote
0 answers
177 views

Equipment to measure strong constant (in time) and slowly changing electric fields

I would like to measure the electric field in the vicinity of an object of interest. I would like to have decent spatial resolution (i.e. be able to pinpoint a measurement to a point in space within ...
Slava P's user avatar
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How to measure power consumption with a hall effect sensor?

I am trying to make a project in which power usage of our daily life devices such as refrigerators, television etc will be measured using a Hall effect sensor and a microcontroller (ARM Cortex-M ...
Zero_Cool's user avatar
1 vote
0 answers
90 views

Definition of "hot" resistor when calculating RMS thermal voltage?

I am calculating the RMS thermal noise voltage of a "hot" resistor of a tutorial sheet for uni. I have used the standard Johnson–Nyquist formulas, but the answer sheet does not include the entire ...
user3474943's user avatar
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34 views

Sizing MOSFET VDS to account for Stepper Back EMF

I'm having difficulty conceptualizing how the Back EMF of a motor, stepper in this case, can damage an H-Bridge MOSFET if the Vds aren't sized correctly. My main issue is my understanding of how the ...
Lpaulson's user avatar
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0 answers
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How to find gain parameter of complementary filter algorithm for application in navigation

I am using mpu-6050 6 axis Inertial measurement Unit for navigational purpose for tracking orientation and position of a vehicle w.r.t starting point, I am trying to improve the orientation tracking ...
Akash Sagar's user avatar
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22 views

What is the relation between the minority charge profile in the base and the collector current (BJT)?

For a BJT in forward active mode, the minority charge concentration at the base-collector junction is zero. If this is the case, how is a non-zero number of electrons able to make it to the collector? ...
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69 views

What goes on inside the transistor that amplifies the signal?

I understand that, for example, in BJT NPN transistor in common emitter configuration used as amplifier, feeding the small signal at the base will produce the larger signal at the collector. But what ...
komrad2236's user avatar
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Calculate complex impedance value from voltage in time domain waveform

I have problem. I was doing an electrochemical impedance spectroscopy (EIS) test on my Randles cell. simulate this circuit – Schematic created using CircuitLab The data from potensiostat's ...
Prayander Sahatma Siahaan's user avatar
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107 views

Why do we subtract horizontal and vertical component of a electric field?

I was solving a question of electrostatic which is: Find the electric field at a distance z above one end of a straight line segment of length L that carries a uniform line large lambda. My question ...
user305532's user avatar
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0 answers
329 views

RGB LED Color Calibration to D65

I am trying to determine resistor values to set the forward current per color of an RGB LED. I would like to achieve approximate D65 (daylight white) when all LED channels are driven at maximum ...
usman510's user avatar
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0 answers
50 views

Calculation of series circuit elements

I have a series circuit. Should it be true for this series circuit if I true to write like: ...
aleksandr's user avatar
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0 answers
132 views

Do you get correct graph of transfer characteristics(CNTFET), if you take +ive Vds(constant) value instead of -ive. As mostly CNTFETs are p chnl FETs

I'm studying transfer characteristic curve of CNTFET to get value for mobility, S.S, etc. According to my basic background knowledge, NMOS curves lie in the 1st quadrant. While for PMOS they lie in ...
user281793's user avatar
0 votes
2 answers
131 views

How do I set up a circuit in order to help me measure the resistance of a 1-meter length copper wire with changes in temperature?

I am a high school student and I am taking Physics at school. I have been given the task of measuring the resistance of a copper wire with changes in temperature, however, I have no prior knowledge of ...
Sogand Golshahian's user avatar
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0 answers
122 views

How do I effectively trip a digital Hall effect sensor with low current. Magnetic field amplification?

This is part of a more complex project for school but here is what you need to know to help me. I have a DC voltage from 0-5 volts I must include a resistive load. The Hall effect sensor trips a ...
Max W's user avatar
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0 votes
3 answers
59 views

How does being exposed to strong radiations effect nanosatellite electronics equipment?

I'm on paper designing a nanosatellite power system. The satellite would be orbiting in LEO. And I am wondering how and what type of radiation would affect its electronics. The system has a ...
Marko Pavlovic's user avatar
0 votes
0 answers
75 views

Since current through capacitor (between the plates) is displacement current, what is the current flowing to the leads of a capacitor called?

Since there is no conduction current through the capacitor, what is the current that flows between the battery and the leads of the capacitor while the plates are charging (or discharging) to their ...
jrive's user avatar
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38 views

Side lobe level of an aperture antenna

There is a electric field in the far zone of the rectangular aperture antenna as shown below. Antenna lies along the xy plane. $$E_{\theta}=\dfrac{jke^{-jkr}}{4\pi r}\dfrac{sin(0.5\lambda k sin\theta ...
Aldrich Taylor's user avatar
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0 answers
22 views

Error Propagation and Analysis on a experiment due to Voltmeter Constraints

I got a situation: at the moment I am unable to access both channels for Keithley 2182A nanovoltmeter using LabVIEW. However, for some odd reason, while I cannot access the channels at once, LabVIEW ...
Enrique Segura's user avatar
0 votes
1 answer
169 views

Bidirectional level translator using N channel MOSFET

I'm using a n channel MOSFETa bidirectional level translator. The case when the body diode conducts the source end will be literally 0V or forward voltage of body diode, so the difference in voltage ...
Vignesh C's user avatar
  • 321
0 votes
1 answer
124 views

Is it logically explainable that current is lower when torque higher?

I am modelling a motor with a little simulation script. The principle is: Input is the traction force needed to be provided by the motor Output is the current to be provided to the coil of the motor (...
totalMongot's user avatar
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0 answers
57 views

Magnetic locks with paramagnetic materials

Well I was wondering why magnetic locks are made of an electromagnet and a ferromagnetic material and not an electromagnet and a paramagnetic material. The magnetic attraction between the ...
Mrs Chemistry's user avatar
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0 answers
154 views

Ordinary LED response to nanosecond pulses

Can anybody explain to me the output waveform generated on pins of an ordinary LED when it is exposed to very short light pulses? I can clearly see that there is a precise difference in the length of ...
Martin's user avatar
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0 votes
0 answers
119 views

Switch to use in high g-force environment?

I need an on/off type switch (spst) on a device that will be subject to high, continuous centrifugal force loads (500-1000G or 5000-10000 m/s2)). Will your everyday, off-the-shelf switch handle this? ...
IronEagle's user avatar
  • 101
0 votes
1 answer
45 views

Electrostatics/conservation of charge

Conservation of Charge states that "Charge cannot be created neither be destroyed." If something cannot be created, then how it is in existence?
Shivank Joshi's user avatar
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0 answers
69 views

How to calculate the current produced by a solar panel?

The equation for calculating current when given voltage and temperature is known as the 5-Parameter model ie. \$I = I_{ph} - I_o[\exp(\frac{V + R_sI}{nV_t})-1] - (\frac{V+R_sI}{R_{sh}})\$ Since this ...
Aakash Sasikumar's user avatar
0 votes
1 answer
61 views

Non-Corrosive Water Sensing

I have been told that passing DC current through two probes in water will lead to corrosion on the terminals. Apparently AC does not cause corrosion. Preventing corrosion is of high importance to me....
MMmmm's user avatar
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0 votes
2 answers
83 views

Effect of electron discrete nature on current density

Coulomb’s law states that the current that flows through a wire is proportional to the applied voltage. For sure there are many physical effects (linear and non-linear) that participates in the ...
PDuarte's user avatar
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