All Questions
9 questions
6
votes
5
answers
697
views
Behavior of BJT collector current in saturation [closed]
Let's assume that we have NPN BJT with absolute maximum rating of collector current = 1A.
Let's assume that we have separate power supplies for base-emitter and collector-emitter.
The collector-...
- 61
3
votes
3
answers
672
views
Why is base current needed after transistor is switched on?
If there already is a current flowing from the collector to the emitter, can’t the electrons just keep jumping over the PN junction?
Why does killing the base current make that impossible?
- 31
4
votes
2
answers
735
views
Designing a common emitter audio pre-amplifier
I am trying to design and simulate a common emitter audio pre-amplifier using 2N2219 with characteristics based on industry standards (audio frequency response, etc. Corner frequency must be less than ...
- 129
2
votes
0
answers
176
views
Why BJT thermal voltage can be not equal to kT/q in SPICE3
In SPICE, apart from effects such as basewidth modulation and base-collector leakage the collector current is given by the expression (according to the original SPICE2 PhD work)
But actually, ...
- 1,177
3
votes
3
answers
490
views
Possible to control a transistor by BC terminals?
I'm thinking about a strange working mode: the CB part is forward biased and trying to control EC current by CB current.
EB is reversed.
May it work?
Transistor is BJT.
- 205
0
votes
3
answers
174
views
Transistor Analysis
Here is a problem I saw as an example of transistor analysis: (hFE is 50)
simulate this circuit – Schematic created using CircuitLab
The process is simple, the guy assumed that the transistor ...
- 167
0
votes
4
answers
8k
views
How to calculate the input and output capacitors of a common emitter amplifier using BJT?
Sorry if the question is stupid, but my head is still hard as a coconut and I am learning...
I am dealing with this circuit that I have calculated from scratch.
This circuit was designed to have
Vc =...
- 847
3
votes
2
answers
1k
views
BJT Voltage Divider Bias Circuit Theoretical/Ideal Model Help ..LTSPICE?
simulate this circuit – Schematic created using CircuitLab
I've been trying to study BJT Voltage Divider Bias Circuits. In particular, as they relate to their active region, amplification, and ...
1
vote
0
answers
70
views
BJTs drawing collector current from a limited current source
simulate this circuit – Schematic created using CircuitLab
Let's make everything ideal by ignoring the voltage drops:
Q1's allowed collector current is: 22.4 mA
Q2's allowed collector current ...
- 187