The situation can be improved by introducing DC feedback to the circuit as shown in Figure 10. The collector current, in this case can be determined by applying Kirchhoff’s law to the Base-Emitter loop.
Rearrange the equation and applying
The collector current is now
Under certain conditions (leave it to student to think about it), the collector current is now less dependent to the current gain.
It, now, depends more on the circuit elements such as VBB, RBB, and RE which are easier to control. In the next experiment, students will see the importance of stable collector current.