
#1
Jan1114, 07:13 AM

P: 56

Hi!
I'm tinkering with a circuit for an amplifier and have a question about entities. What's is the difference between β (h_{FE}) and β_{max}? 



#2
Jan1114, 07:58 AM

P: 389

Even if you just have full bucket of transistors of the same type (2N2222). Each of them will have a slightly different beta. So the BJT vendors in data sheet tell as that in our bucket we will find transistors with beta value between Hfe_min and Hfe_max. But most of our transistors will have a typical value of beta also given in the datasheet.
And when we design the amplifier circuit we always pick Hfe_min form datasheet. 



#3
Jan1114, 08:02 AM

P: 56

Ok... How would I interpret these different betas?




#4
Jan1114, 08:14 AM

PF Gold
P: 5,705

question about βmax 



#5
Jan1114, 08:16 AM

P: 389

I don't understand your question?
Transistor beta (Hfe) is not constant and datasheet for every transistor part number gives a range for Hfe, also every transistor has its own unique Hfe value. The Hfe is a range of numbers because they cannot make transistors accurately. Also the Hfe changes when the collector current is changed and the hfe changes when the temperature changes. 



#6
Jan1114, 09:14 AM

P: 56

Sry, I forgot to think before I posted the last one.




#7
Jan2014, 01:09 PM

P: 24

is it true you can only use hparameters for dc analysis? I know ebersmole is their but I don't know calculus.




#8
Jan2014, 08:08 PM

Sci Advisor
PF Gold
P: 2,633





#9
Jan2114, 08:42 AM

P: 389





#10
Jan2114, 07:04 PM

P: 377




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