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Hfe question...

trgf2250

Oct 23, 2015
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Oct 23, 2015
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Hello, I'm using Pspice first time.
what is exactly "Maximum forward beta"?
I thinks that means beta, but if i use only 1mA, or more
then maxium beta would be changed.

and what value is beta - usally call just 1 value.....
what is standard?
 

Colin Mitchell

Aug 31, 2014
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Aug 31, 2014
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The collector-emitter voltage is very high in the example above.
Normally you want the c-e voltage to be less than 0.5v (for a number of reasons) and this is the first thing you should sort out.
The next thing is to add a load to the circuit and work out how much current will flow through the load.
Suppose it is 100mA.
Then you assume the transistor has a gain of 100.
This means the base needs 1mA.
Can you supply 1mA to the base?
Then you use a transistor that will pass 200mA or MORE and put it in the circuit.
Use a transistor with a rating of 200mA to 500mA.
If the voltage is more than 12v, you may need to look at the voltage rating of the transistor.
That's the simple approach.
 
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