All Questions
Tagged with semiconductors voltage
26
questions
1
vote
3
answers
70
views
Seebeck Voltage [closed]
I understand that the voltage of two metal elements is V=(Sb-Sa)(T2-T1) regarding a thermocouple. But, what if mass was introduced to find the voltage? Can mass also be used to find voltage with ...
- 11
8
votes
4
answers
2k
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How can I clip a voltage upper limit in an analog signal?
This is a theoretical question since I've come across this type of problem many times.
Suppose an amplifier is powered between 12 V and -12 V, so the signal output can reach a maximum of 12V. If I am ...
- 532
0
votes
1
answer
403
views
Fermi levels in PN-junction under forward bias are not constant throughout each side
This is, in a way, a follow-up to this question.
I see the following band diagram for a forward biased diode everywhere:
In the above picture, I marked a point with potential zero (where battery is ...
- 163
16
votes
5
answers
4k
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Resistance depending on voltage - the chicken and the egg?
If I understand correctly:
The resistance of some circuit components (like diodes) depends on the voltage across them.
When two components are connected in series: \$\frac{V1}{V2} = \frac{R1}{R2}\$
...
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1
vote
0
answers
111
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When does the transistor reach the stable status when I add resistor to the emitter
simulate this circuit – Schematic created using CircuitLab
If I add resistor R3, which is an emiter resistor, can it change the value of the base voltage? I've learned that the emmiter voltage ...
- 183
2
votes
1
answer
993
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What is the exact meaning of 0.7V voltage drop in a forward-biased diode?
this question is partially (but not totally) discussed here:
Why do diodes have a voltage drop?
Does the power drop on a diode become entirely heat?
The conclusion is that, in a forward-biased diode ...
- 3,550
-1
votes
1
answer
199
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What happens when an LED burns out? [duplicate]
When an LED is burned out, specifically which part is burned out?
Is it the semiconductor or the wires?
Can we use a burned out LED to generate electricity?
0
votes
0
answers
267
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Simulating circuit TINA TI
For my assignment I got to run a transient analysis for the duration of 5 periods of sinusoidal input voltage and display the input voltage (ac + dc) and the output voltage on the RL component.
Used ...
- 1
2
votes
2
answers
162
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How can you measure voltage differences less than thermal voltage (~26mV at room temp)?
If thermal voltage is the average voltage of any given electron relative to the voltage at ground state, and this presumably fluctuates, how can you make any measurement on a circuit more accurate ...
- 398
1
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4
answers
2k
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Why does the base-emitter voltage in NPN transistor become constant?
The setup above shows the experiment that I have been working with. During the experiment, the current \$i_c\$ and the voltage \$V_{be}\$ were measured for increasing \$V_{in}\$. At some point, the ...
- 13
1
vote
1
answer
73
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Question about transitor NPN [ALFA;Strange configuration;Exit characteristic]
first of all thanks for read and for your time, I have a few questions about transistor:
1)
I can't understand why my book say:
Ic=Icb0+alfa*Ie
and not ...
- 13
0
votes
2
answers
262
views
Forward voltage across the diode
If the diode's dynamic resistance was zero , will not we be able to increase the voltage across the diode above 0.7 v ?
(I am assuming forward bias )
I am asking this question because my book ( ...
- 37
1
vote
2
answers
122
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Designing a circuit that opens when less than 12 volts are applied and closes when more than 12 are applied
I'm looking to build a circuit where current only flows when there is a potential difference across the entire circuit of more than 12 volts (+- 0.1 V). I also need there to be only a small amount of ...
- 203
1
vote
2
answers
285
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Cause of triode mode in MOSFET
My reference text introduces the MOFSET as follows:
The text says the induced channel has uniform width as long as \$v_{DS}\$ is small, because in that case \$v_{GD} = v_{GS} - v_{DS} \approx v_{GS}\$...
- 137
0
votes
2
answers
988
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Easiest way to create a constant 1V voltage drop [closed]
I need to find a small, cheap, easy way to get a 1V drop in a circuit. It needs to be such that below 1V it acts like an open switch, and above 1V the drop is a constant 1V. Basically an LED without (...
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1
vote
4
answers
493
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Is forward biasing or reverse biasing an inherent property of a diode?
I read a tutorial about transistors and I reached the following sentence.
"The Bipolar Junction Transistor (BJT) is a three layer device constructed form two semiconductor diode junctions joined ...
- 803
0
votes
2
answers
167
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Operating semiconductors outside of Voltage specifications?
If I were to employ the schematic below will the transistors survive.
I ask this because I was able to operate 3 low voltage(I'm guessing 1.5v), run of the mill junk LED's in series at a voltage of ...
- 235
4
votes
1
answer
5k
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Measuring barrier potential of a pn junction using a voltmeter
The image above is from the book "The Electronics companion". Can someone please explain why the barrier potential of a pn junction cannot be measured due to the presence of the contact potential?
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0
votes
1
answer
354
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Does input signal mean same as input in transistors as amplifier?
During solving [this question] I came across a term input signal, I want to know whether input signal means the input voltage or change in input voltage? I am unable to solve if I take input signal as ...
- 169
3
votes
3
answers
1k
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LED typical and forward voltages
So, I was going through the spec sheet of super bright 5mm orange LED, and it was listed that the forward voltage is between 1.8V and 2.5V. Below that there was a property listed as 'typical voltage' ...
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2
votes
0
answers
388
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What does the channel voltage in a MOSFET really mean and how does it lead to the Fermi level splitting shown?
Many books (Chenming-Hu Ch.6 Page 15, Neamen Page 413) use the term 'channel voltage' \$V(y)\$ to mean 'the potential in the inverted channel at a point \$y\$ distance away from the source along the ...
- 165
1
vote
1
answer
875
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How does a junction-less transistors work?
I have recently read in a book that in 2010,junction-less transistors were developed.
I can't understand how a junction-less transistor can be used to amplify current or voltage with having any ...
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0
votes
1
answer
3k
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Cutoff and Conducting diodes
Why is D1 considered cutoff and D2 considered conducting ?
Note : I am working with constant voltage model where the diode voltage is 0.7v and I need to figure out I and V. Please explain why D1 is ...
- 178
45
votes
8
answers
11k
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Why isn't there a potential difference across a disconnected diode?
I know this question sounds silly, as if there was a potential difference a current would be created when the terminals are connected together and this would mean energy has come from somewhere.
The ...
- 1,655
2
votes
1
answer
477
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Potential drops in BJT in CE configuration?
In a simple p-n junction diode, there is a \$V_{eq}\$, the potential difference between the p-doped and the n-doped portion of the diode. When an external potential \$V\$ is applied in forward bias, ...
- 169
2
votes
0
answers
60
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Built-in voltage [duplicate]
Hello all I have work on the following question and just wondering if you all could check to see if i did it correctly.
The built-in voltage of a GaAs pn junction diode is 1.25 V when the diode's ...
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