BJT biasing formulas

[audioguru2]

when I have to choose higher values for Ic?

1) When the load requires a higher current.
2) When the output capacitance of the transistor and stray capacitance combines with the collector resistor's value to form a lowpass filter. A lower value of the resistor would require a higher collector current for a higher frequency response.

 

[walid1]

2) When the output capacitance of the transistor and stray capacitance combines with the collector resistor's value to form a lowpass filter. A lower value of the resistor would require a higher collector current for a higher frequency response.

Please I want further clarification on this point, I hope to support that with examples and illustrations
thanks

 

[audioguru2]

A transistor's output impedance is the value of its collector resistor. The collector resistor is the signal source and the capacitance of the transistor's collector plus stray capacitance forms a lowpass filter with it.
If the value of the collector resistor is lower then the collector current would need to be increased but the lower resistor value makes the frequency higher of the lowpass filter.

I have forgotten all the high frequency transistor formulas that I learned more than 40 years ago and have never used. Maybe you can find examples and illustrations on the internet.

 

[walid1]

Thank you guru, I think that this is a big subject
it is better to focus now on topics simple and and when finished turn to the more difficult topics.

I want to tell you that a great honor for me to debate with you, you great wealth of scientific.