# Increasing in slope result in increasing in impedance of BJT Early voltage?

I'm studying about the AC equivalent model of BJT and in the re model, it said that:

"As the base current increases the slope of the line increases, resulting in an increase in output impedance with increase in base and collector current"

I thought that the impedance is equal to the ro in the denominator, so base on the formula of the slope in the picture then if the slope increases, the value of ro decreases and therefore the impedance should decrease rather than increase.

Am I missing something?

• The "steeper" the slope is the lower the ro resistance is. i.stack.imgur.com/gV6wP.png
– G36
Mar 28, 2020 at 17:12
• Where did you read such surprising "explanations"? I suppose - any obscure internet source?
– LvW
Mar 28, 2020 at 17:36
• Electronic Devices and Circuit Theory (11th Edition) by Robert L. Boylestad, Louis Nashelsky - page 259. That's why I felt so confused because it's in a textbook. Mar 28, 2020 at 17:39