the early effect voltage

A

andrebc

New Member

• Jun 30, 2009

• #1

Hi all,

does any body know how I get the value of VA,the early voltage effect of a BJT from the transistor data sheet. I need to get that so I can calculate the ro of an amplifer.

Thank you

 

J

Jony130

Active Member

• Jun 30, 2009

• #2

Look for hoe in datasheet
Hoe=1/ro
For example for the BC548A
https://www.electro-tech-online.com/custompdfs/2009/06/85113.pdf
We can read form datasheet that Hoe=18uS for Ic=2mA and Vce=5V.
VA=Ic/hoe≈110V
Or we can read the Hoe for different Ic current from the graph "Relative h parameters versus collector current"

 

T

The Electrician

Active Member

• Jun 30, 2009

• #3

You can find a good explanation here:

**broken link removed**

and here:

Early effect - Wikipedia, the free encyclopedia

 

A

andrebc

New Member

• Jul 2, 2009

• #4

thank you all that helped a lot