All Questions
Tagged with semiconductors transistors
14
questions
16
votes
3
answers
8k
views
Can a thyristor be built from two transistors?
Supposedly, an SCR/thyristor is just a simple, four layer PNPN semiconductor.
If that's the case..
When a circuit calls for a SCR/thyristor, and there isn't one available, can it be substituted by (...
- 1,089
14
votes
1
answer
8k
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Where are the depletion PMOS transistors?
In school, I was taught about PMOS and NMOS transistors, and about enhancement- and depletion-mode transistors. Here's the short version of what I understand:
Enhancement means that the channel is ...
- 17.6k
5
votes
2
answers
3k
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Are BJTs used in modern integrated circuits to the same extent as MOSFETs?
On modern integrated circuits, are there as much BJT's on the chip as MOSFET transistor? If not, why?
- 377
12
votes
4
answers
18k
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Why can current flow through the reverse biased base-collector junction (N-P junction) in a BJT with a forward biased base-emitter junction?
If the base-emitter junction of a BJT is forward biased, then current can flow through the reverse biased base-collector junction (N-P junction). This disagrees with my understanding of the PN ...
- 1,655
6
votes
4
answers
949
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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 ?
4
votes
1
answer
2k
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Modelling and simulating multiple-collector/emitter BJTs
I occasionally like to try to understand how well-known integrated circuits work by building them up in a simulator and observing how they respond to changing conditions. However, I keep coming across ...
- 35.2k
3
votes
5
answers
3k
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Why reverse connected MOSFET start to turn on at Vgs<Vth?
The circuit shown below is implemented using two AO3400 N-MOSFETs.
AO4300 datasheet here.
The right-hand MOSFET is connected with normal polarity (Vds is positive),
while the left-hand MOSFET is ...
- 93
2
votes
1
answer
282
views
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 ...
- 133
2
votes
2
answers
1k
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Identifying parts of a transistor die
In books, I have studied that in a Transistor, the Base is the layer sandwiched in between Collector an Emitter. Wikipedia also mentions that
"The base is physically located between the emitter ...
- 346
2
votes
3
answers
1k
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Why Collector-to-Base currents ratio in a BJT transistor is always greater than 1?
In fact, this question has been asked on the EE site, but it's not well-answered. I suppose it might be more on-topic here.
According to this answer:
Note that the holes injected into Emitter are ...
- 329
2
votes
1
answer
2k
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If the depletion layer of a transistor collector/base junction is thick, why are majority carriers still collected?
In "Principles of transistor circuits, 8th edition" (top of p26) it is said that once holes have been injected in the base region by a forward biased base-emitter junction (which I understand) of a ...
- 9,906
0
votes
2
answers
3k
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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 ...
- 1,831
0
votes
3
answers
2k
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How exactly does a transistor amplify the input current in CE configuration
I have gone through tons of forum discussions and videos and books but they all explain in terms of mathematical equations that factor the input by a 'larger than 1' number. What happens physically ...
- 3
0
votes
2
answers
120
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Transistor: Getting “incorrect” graph for input voltage to output voltage
I tried drawing the graph of \$v_o\$ vs \$v_i\$ for a bipolar junction transistor. I used the below setup (common emitter:)
By design of how the base is a small part compared to others, \$I_b <<...
