[SOLVED] dc current gain variations

[Zak28]

Does hFE vary while BJT is in operation within the specified hFE min/max ranges?

https://www.mouser.com/datasheet/2/408/TTA0002_datasheet_en_20131101-1144060.pdf

 

[FvM]

It does not vary. The min to max range is specified to take account of type variations. If a transistor exemplar shows e.g. B=100 under specific condictions (like Vce=5V, Ic=1A, t=25°C), it will keep this current gain.

 

[Audioguru]

A transistor in operation heats or cools which affects its hFE.
A transistor in operation has a variable current which also affects its hFE.
Design a transistor circuit with enough base current so that it works with the minimum or maximum hFE for the varying conditions. Negative feedback is usually used.

 

[schmitt trigger]

Be aware though, that the specified Hfe is in the linear region. Which in this instance, it means a Vce of at least 5 volts.

As the transistor approaches saturation, the Hfe will start to drop.