All Questions
Tagged with semiconductors transistors
118
questions
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BJT transistor working and construction
Why is electron concentration zero at collector side of the base in BJT transistor? And if electron concentration decreases with distance and becomes zero at the end base region how can it produce ...
CommunityBot
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2
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Why is the Collector current of a BJT transistor independent of the Collector Base voltage?
Ignoring the modulation of the effective base width, why is the collector current independent of the reverse bias voltage across the Base-Collector P-N junction? On one hand, it is easy to see that ...
- 25.3k
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Diffusion Current for Non-Linear Charge Carrier Configurations
Diffusion current in a MOSFET device can be calculated using Fick's Law per \$J=-qD\frac{d \rho}{dx}\$. It is often taken that the charge carrier configuration (\$\rho\$) across the MOSFET channel is ...
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What is a precise definiton of "cut-in" voltage as applied to diodes?
What is the "cut-in" voltage or knee voltage of a diode or transistor?
In a lot of books I read that the cut-in or knee voltage of a diode (or transistor) is when the diode starts conducting ...
- 169k
6
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MOSFET switching on
I have a doubt. Consider an N-MOSFET: which is the voltage that can switch on it? The voltage between Gate and? Sometimes I read "between Gate and Bulk", sometimes "between Gate and Source", sometimes ...
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Bipolar Junction Transistor operating modes
If I use a BJT transistor as a switch, the transistor operates in the saturation or cut-off region, not in the active region.
However, some sources use the formula IC = β·IB. However, this formula is ...
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Why aren't semiconductor wafers diced into triangles?
Semiconductor wafers are circular, and usually they are divided into squares or rectangles. However it's more efficient to pack triangles into circles than it is rectangles, so less wafer area would ...
- 136
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How do P-type transistors conduct current?
Going through a Introduction to Computing Systems by Yale N. Patt and Sanjay J. Patel and currently reading a chapter on MOS transistors. From what I understand, N-type transistors "close" a ...
- 55k
6
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4
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In a JFET, is the gate *always* connected to the bulk/substrate?
In a JFET, is the gate always connected to the bulk/substrate ?
Or is there "no rule" (sometimes it is, sometimes it is not)?
And what about the case of the MOSFET ?
- 3,385
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2
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UJT Negative Resistance and Ohm's Law
A Unijunction Transistor has a negative resistance region where voltage drops with an increase in current. This was explained to me as a situation where "Ohm's Law is broken". This doesn't sit well ...
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Can I calculate beta by using the quiescent point and a voltage divider?
How can I calculate beta with only the data in the image?
Q is the quiescent point. I've tried with the basics Vcc formulas, but since it doesn't provide any value for Vcc I could not proceed.
- 25.1k
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Effect of semiconductor doping on threshold voltage
After reading online, I have modeled this as an relation between the threshold voltage and the doping concentration:
For a N-channel MOSFET on a P-type substrate:
$$
V_{T,N} \propto \sqrt{N_{A}}
$$
...
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2
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Emitter current and Early effect
I know that due to Early effect in a npn transistor the effective base width reduces.However I can't understand how this will lead to an increase in emitter current.
Some sources say that the charge ...
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3
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Connecting only emitter to collector-BJT
I started studying the BJT Configurations and how they operate in active mode, saturation mode, and cutoff. And that every two neighboring junctions have either forward or reverse bias, But I wonder ...
- 25.3k
2
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3
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What exactly happens at the fundamental level if base voltage is higher than collector voltage in CE transistor?
In the first answer to this question, it is stated that:
This happens even if the base and collector are at the same voltage (!). Basically, one way to model a transistor is as the base-emitter diode,...
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