In a bipolar transistor, the current from base to emitter creates a current from collector to emitter that is Beta times the base current. The emitter current is Ib*(Beta+1) and the collector current is Ib*Beta.
samcheetah said:In a bipolar transistor, the current from base to emitter creates a current from collector to emitter that is Beta times the base current. The emitter current is Ib*(Beta+1) and the collector current is Ib*Beta.
thanx but i already know that and i also said that in my post. thats the way of seeing it as a current controlled device. altho it is not a good way to visualize the "transistor action" it does provide answers to a few questions
my question was something else.
a transistor IS! a current controlled device - and it is the only way to visualise the 'transistor action' (as you called it).
The voltage between base and emitter is pretty well constant, it's not voltage controlled - thinking of it as so will prevent you understanding how circuits work
Beta is defined as Ic/Ib. An emitter resistor does not change this fact.Ic = BETA * Ib
whereas everyone knows that BETA changes alot so we dont use the transistor in this way. one way to get rid of this is by including the emitter feedback resistor. in that case Ic is not equal to BETA * Ib.
samcheetah said:my question was something different which nobody has been able to answer
PLZ READ MY QUESTION FIRST
why is it that whenever i post a question in this forum nobody seems to give me the answer.
Your question has already been answered, it's meaningless!.
In your formulas you ignored the most important part - Ie is not equal to Ic, Ie = Ic + Ib.
Bipolar transistors require base current, they are current driven
samcheetah said:its not i who ignored it. thats why we use the feedback resistor i.e not Ib and BETA involvment
Bipolar transistors require base current, they are current driven
but at the same time we dont want that controlling current. right?? so how does that current control the transistor.
i know that there is some base current in every BJT circuit. but that doesnt mean that it is controlling the output. that is one of the major drawbacks of BJTs that it draws base current.
plz do have a look at the article
i know most of u think that BJTs are current controlled devices (even my electronics teacher teaches us that). All over the world people consider the transistor as a current controlled device. and i dont have any problem with it
the problem is that the current controlled model has a flaw and it doesnt apply everytime.
plz read the article and my recent posts and then think about it.
dont try to shove this current controlling stuff down my throat. it is convention to think of the BJT as a current controlled device because it is easy to explain but that doesnt mean it is true
[/quote]samcheetah said:Your question has already been answered, it's meaningless!.
no it hasnt been and it does have a meaning if u once read it :lol:
In your formulas you ignored the most important part - Ie is not equal to Ic, Ie = Ic + Ib.
its not i who ignored it. thats why we use the feedback resistor i.e not Ib and BETA involvment
Bipolar transistors require base current, they are current driven
but at the same time we dont want that controlling current. right?? so how does that current control the transistor.
i know that there is some base current in every BJT circuit. but that doesnt mean that it is controlling the output. that is one of the major drawbacks of BJTs that it draws base current.
plz do have a look at the article
i know most of u think that BJTs are current controlled devices (even my electronics teacher teaches us that). All over the world people consider the transistor as a current controlled device. and i dont have any problem with it
the problem is that the current controlled model has a flaw and it doesnt apply everytime.
plz read the article and my recent posts and then think about it.
dont try to shove this current controlling stuff down my throat. it is convention to think of the BJT as a current controlled device because it is easy to explain but that doesnt mean it is true
in a common collector configuration what is the situation. the voltage between which two terminals is controlling a current through the third terminal. please explain. thanx in advance
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