PNP Transistor AC Amplifier Circuit!

[@transformateur9969]

Hello, interesting but there are two points that I don't understand, where does the multiplication by 10 at 7:16 come from? And at 9:17 the multiplication by 9? THANKS

[@4abrownafrica420]

As a general rule, you multiply by 10 and 9 to get the base current through the base and not through the back resistors. You could also multiply by 11 and 10.

[@clarencegreen3071]

The idea is to have the current flowing through the base resistors "large" in comparison to the base current so that the base current has little effect on the output of the voltage divider formed by the base resistors. Therefore, 10 is an arbitrary number.