about transistor biasing method

about transistor biasing method

screenshot-17-.png

see the above image .in first circuit i added 0.1 ohm resistance i got around 6 v in emmiter side.and then i replaced it with 2.1k then i got 11v as out put .this is why and my supply is 12 v

plzz help me

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chuckey said:

With an emitter load of the DVM (10M ohms), what you are measuring is thermal leakage current, the answer should be ~0V with any reasonable load.
Frank

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Bhuvanesh Nick said:

dvm means and what it meant 10m ohms.

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goldsmith said:

Hi Bhuvanesh Nick
As "FvM" mentioned above you are destroying your transistor in first circuit . when a transistor is about to be biased in active region CB junction must be at reverse bias . and BE in forward bias . and of course the current of that must be limited via a suitable resistor in avoid that our transistor being destructed .
When you want your BJT being saturated concept says the CB junction must be in forward bias but it doesn't mean that we make it a forward bias . it would be in forward bias by behavior of your circuit automatically . the reason that BE should be in forward bias in active region ( instead of CB ) is that BE can go through the zener region and deliver avalanche breaking after 5 volt ( approx ) and we don't want that .

Best Wishes
Goldsmith

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When you want your BJT being saturated concept says the CB junction must be in forward bias but it doesn't mean that we make it a forward bias . it would be in forward bias by behavior of your circuit automatically

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what this sentence means..plz some more detial explaination and what is fvm?

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When you want your BJT being saturated concept says the CB junction must be in forward bias but it doesn't mean that we make it a forward bias . it would be in forward bias by behavior of your circuit automatically

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goldsmith said:

Ha ha ! What is ? you'd better to say who is . everybody know him here as well . he is the guy which his post is above my post . he is one of the most expert engineers that you can see during your life .


"FvM" has explained the point as well in his post : #8 .


Good Luck
Goldsmith

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FvM said:

Did you intend to forward bias the collector-base junction as shown in the schematic? You would destroy the transistor in the first circuit.

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Bhuvanesh Nick said:

my intention is is to make it as swith. for that if i use resistors on collector and base is the works good

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if i use resistors on collector and base is the works good

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.my intention is is to make it as swith. for that if i use resistors on collector and base is the works good

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