Questions tagged [common-collector]
A common collector amplifier (also known as an emitter follower) is one of three basic single-stage bipolar junction transistor (BJT) amplifier topologies, typically used as a voltage buffer.
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Magnitude of \$I_{CBO}\$ in a typical transistor
I read in a book that \$I_{CBO}\$ doubles for every 10 degree rise in temperature and hence contributes to thermal runaway. However I am confused since essentially it is the reverse saturation current ...
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82 views
BJT common collector amplifier with a voltage gain sligthly higher than one
How could I explain why a common collector amplifier has a voltage gain higher than one ? In a lab session, I built this circuit :
With Vg=30 mVpp and Vcc=15V, students were asked to give the voltage ...
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76 views
BJT (Common-Collector Configuration)
As we know that for the transistor to operate in the active mode, it should have emitter-base junction as forward bias and collector base junction as reverse bias. So the common-collector ...
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1answer
62 views
Capacitor in common collector circuit
I have a question regarding \$C_1\$ capacitor - do we really need it in this circuit if we know, that the input signal will have no offset (i.e. \$\overline{V_{IN}}=0V\$)?
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243 views
Common collector transistor
According to my understanding the common collector transistor should be like figure-1 but in book it is given as figure-2 and in it Vcc is given.Can anyone provide me proper explanation of this.
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A good and valid example of Common Collector BJT
I am analyzing a common collector BJT as an amplifier using LTSpice. I have made the following circuit and I am not getting the exact characteristics which I should have got.
Is there something wrong ...
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1answer
516 views
How to determine the input resistance of a bootstrapped emitter follower
I've used bootstrapping several times, either to boost the input impedance of an amplifier or to increase its gain. However most of the times I can see the beneficial effects of bootstrapping without ...
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134 views
Identifying the configuration of transisitors
I have been handed the diagram below, as part of an introduction to transistors.
I am having a hard time finding out what type of configuration it is, therefore making it even harder for me to find ...
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807 views
Emitter follower/Common collector confusion
I'm in the need of a buffering circuit for a project and I would like to use a common collector amplifier or emitter follower for this purpose. Above is a schematics of the circuit I'm looking into.
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Understanding common terminal in common collector/emitter amplifier
I am beginner in electronics and trying to understand some basics. One thing that confuses me is transistor configuration with common terminals. Since transistor has three terminals then we must use ...
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2answers
967 views
Single supply op-amp voltage follower - negative clipping with AC-coupled load
I am using a µC running DDS algorithm to synthesize certain waveforms (in fact I made 3 channel music generator with portamento&ltude modulation effects, commands for changing waveforms etc. ...
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199 views
All possible BJT circuits relating to polarity
The BJT can operate in 4 different modes/zones since there are two voltages on it:
Active mode
Inverse/Reverse active mode
Saturation mode
Cut-off mode
Because Emitter and Collector junctions can ...
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1answer
259 views
Transfer function and frequency of Common-drain Colpitts with ballast coil
Whilst looking for a circuit to test some unidentified RF filters and coils I have lying about, I came across a FET based Common-drain Colpitts used in this youtube channel hosted by RF enthusiast ...
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Common Collector Biasing
The common terminal of the transistor configuration is also the GND of the circuit, right? I get it that emitter is GND but how is it possible for NPN transistor that base or collector is GND?
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Misunderstanding of amplifiying a current with transistor
Electrical books say that we can use transistor to amplifying current but when I simulate a circuit in proteus input current, it is smaller than emitter current but why?
This is a common collector ...
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1answer
2k views
CC-CE multistage amplifier
I've an unsolved exercise to ask.
The circuit is shown below:
The first question ask to find a value of R2 for which Vout = 0 with Vin = 0.
I think this question is referred to the small signal ...
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1answer
579 views
Common collector amplifier current amplification [duplicate]
given:
Re = 500 Ω
Rb = 261 kΩ
What can we tell about the current amplification? Is this circuit useful?
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2answers
257 views
BJT Common Collector not swinging “negative”
I have an R2R DAC generating a 0-3.3V sine wave. This sine wave is fed into a non inverting op amp with a gain of 2. Then I'm trying to drive a 0.5W 50ohm speaker with a common collector amplifier. ...
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Cascading Common-Emitter Common-Collector for maximum power transfer
Hi Am trying to understand what am doing wrong, I connected CE to CC with a small Rload am designing it so Zout of the second stage equal Rload to get Maximum output.
From what i read in CC-amp Zout =...
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How does this power supply circuit work?
This is the circuit of a power supply with adjustable output voltage and current, and I wish to understand how it works:
What I did understand:
R1 T1 VD5 - they form a voltage divider which provides ...
