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amplifier factor of transistors.

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yafch

New Member
hello,
how can i know the amplifier factor/amplification factor of a transistor, specially when there is a need to know the amplifier factor of power transistor.Datasheets contain this factor?. i cant find it in any of datasheets those i have.

thanks.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
There's no such characteristic, they have the current gain shown in the datasheet, and probably a graph for current gain at various collector currents as well.
 

yafch

New Member
i was reading a web page for psu design and the designer specifically wrote about to take care of this factor for output transistor. He wrote that the amplifier factor of the power transistor should be between 40-70. and in no way it should be above 70. any way it was the only page where i read about it for the first time. thanks for help.
 

Willbe

New Member
hello,
how can i know the amplifier factor/amplification factor of a transistor, specially when there is a need to know the amplifier factor of power transistor.Datasheets contain this factor?. i cant find it in any of datasheets those i have.

thanks.
The current gain of a BJT [a current-controlled current source] is given by beta or Hfe. The voltage gain and the power gain depends on the circuit resistances.

FETs are voltage controlled current sources.

Post a datasheet; we can help you wade through it.
 

Ayaskanta

New Member
What do you need it for? If it is for designing then you must consider the maximum value. If you are calculating practically then take the ratio of the input current to the output current.
 

wizard

Member
yafch,

What are you meaning by ''amplifier factor/amplification factor of a transistor''?

Maybe you are referring to Current gain of a transistor, so called 'Beta' or 'Hfe'?
The current gain for a transistor when OPERATING is equal to Collector current divided to Base current. If you divide those currents, you will reach a number (it is unitless), the said number tells you the rate of current gain or current amplification of the transistor at that operation point.
For common transistors beta is between 200 to 400 but most designers tend to use a Beta much less than those numbers in their designs.
makes sense?
 
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