The physics tag has no wiki summary.
3
votes
1answer
56 views
Impact of the channel length on the threshold voltage in CMOS transistor?
Is there a monotonic relation between the channel length and threshold Voltage and is it proportional or inverse?
4
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3answers
152 views
How are charges moving?
I am trying to understand a problem I did once with capacitors. I am not a native English speaker so I am translating it, I hope you can understand it:
A capacitor C2 is charged with 10V, then, ...
0
votes
1answer
56 views
books/topics to get started on physics of semiconductors
i would like to know enough about the physics of semiconductors to the point that i can extrapolate certain properties of custom semiconductor pieces. i'll mostly be using Technology CAD to simulate ...
4
votes
1answer
114 views
What ultimately determines the speed of electrical media
I have heard several myths about this. Some have said "thicker wires mean faster speed" which I don't believe. Others have said different voltages and others have said higher frequencies.
Take Coax ...
4
votes
2answers
133 views
How does electricity produce heat, and where do the electrons go?
When electrons flow through a conductor it is subject to resistive loss, which has the unfortunate capability of producing heat from this current, leaving us with less current in the other end of the ...
8
votes
6answers
613 views
Why does the thickness of a wire affect resistance?
A teacher explained why by using a highway analogy. The more lanes you have, the faster the cars go through, where the number of lanes obviously represent the wire thickness and the cars represent ...
23
votes
5answers
854 views
How fast does electricity flow?
I get confused on the low-level physics of electricity from time to time. It came up in "Which way does electricity power a circuit," and I don't totally get it.
How fast does electricity flow? Is ...
2
votes
1answer
109 views
Static electricity discharge, what gets transfered?
Ive been studying Maxwell equations at school and I solved several excercises regarding electrostatic fields, however I still have some very basic unanswered questions:
When a non conductive object ...
0
votes
1answer
102 views
Find the peak load of a power plant for the given load equation
The daily load demand of a grid is given by
$$P=P_{max} \cdot cos(\pi t/24)$$
Here \$-12hrs ≤ t ≤ 12hrs\$. Maximum power occurs at (\$t=0\$) and minimum occurs at (\$t= ±12\$). A \$10 GW\$ hydro ...
16
votes
3answers
339 views
MOSFET: Why the drain and source are different?
Why the drain the source terminal of the MOSFET function differently while their physical structure is similar/symmetrical ?
This is a MOSFET:
You can see that the drain and source are similar.
So ...
4
votes
3answers
531 views
How does a dual gate MOSFET reduce Miller effect?
How does a dual gate MOSFET reduce Miller effect? I am trying to gain a global understaning of the physics behind them, not necessarily exact formula's that come with it other than maybe some for ...
-7
votes
1answer
104 views
Does the anticircuit exist? [closed]
Are there anticircuits like antmatter? Maybe poles are reversed and condensors become resistors and everything else is reverse. I wonder if so if one day things that suck power like heaters might ...
-3
votes
2answers
235 views
Two spheres capacitors
A capacitor consisting of two concentric spheres of radius R1 and R2 = 2.50·R1 has a capacitance of C = 6.00 picoFarads and is charged to a potential difference of 74.0 Volts.
Calculate the energy ...
2
votes
1answer
146 views
Physics/chemistry understanding of PMOS and NMOS to form CMOS
Can anyone provide me explanations or links that provide a clear explanation of what atoms/molecules are in p-type and n-type (PMOS/NMOS) and how they interact to create actions?
8
votes
1answer
4k views
What is the difference between emitter and collector for BJTs?
the (surely simplistic) model of a bipolar junction transistor one is taught in foundational physics course appears to be symmetric. - So, what is the difference between the collector and the emitter ...
3
votes
3answers
287 views
Electro Optics vs Optoelectronics > What's the difference?
I've seen both wikipedias of Electro Optics & Optoelectronics but I'm still confused on what the difference is.
I'm currently pursuing a degree in either Physics or Electrical Engineering because ...
-1
votes
2answers
128 views
Charge moves if you scuff the rag with your shoes [closed]
Why is that when you scuff with your shoes on, charges move (since electrometer moves back and forth), but if you dont have your shoes on, the electrometer doesnt move
Here is the corresponding video ...
1
vote
1answer
131 views
Help with connecting electromagnet to dimmer
I have an electromagnetic powered off a AA battery. Is there some kind of dimmer switch or similar item that would allow me to control the amount of power going to the electromagnet?
11
votes
2answers
1k views
How does a nine volt battery make a spark?
With a nine volt battery, touching the two terminals together (or using a faulty terminal) will cause a spark roughly where I would want it to be.
How is this possible? Is it ionizing only a very ...
3
votes
1answer
132 views
Creation of Trap Levels in Band Gap Energy
When I started reading about basics of semiconductors, I read that no electron is present in the band gap energy and it is a sort of forbidden area for them.
But just now I read that some trap levels ...
2
votes
3answers
305 views
Why can you use an LED below voltage?
If you put too little voltage across an LED, nothing happens, as I would expect. However, I've seen a demo where a red LED is powered with a 1.5V cell, and it lights. I assumee that red LEDs are ...
6
votes
3answers
3k views
How do BJT transistors work in a saturated state?
This is what I know about NPN BJTs (Bipolar Junction Transistors):
The Base-Emitter current is amplified HFE times at Collector-Emitter, so that Ice = Ibe * HFE
...
11
votes
7answers
714 views
Which everyday components involve flows of charge that are not electrons?
I like this explanation of why there's nothing wrong with conventional current being the opposite direction from electron current. It mentions batteries and fluorescent bulbs as two cases where the ...
2
votes
1answer
113 views
Bonding in intrinsic semi-conductors
In the intrinsic semi-conductors,the electrons are bonded by covalent bonds to the nearby electron,when we do doping the electrons make bond with the atom we doped,so the covalent bonds between the ...
