Transistor Voltage Divider

Thread Starter

jmsparkland1

Joined Feb 29, 2012
7
In Volume 3, in the chapter on bipolar transistors, the author writes about how to practically forward bias the transistor. He does this by creating a voltage divider with two transistors. How did the he figure out what two values of resistors to use? Obviously I understand Ohm's law, but how could he decipher which values would be appropriate? Any help would be appreciated.
 

Potato Pudding

Joined Jun 11, 2010
688
Looking at those values?

I suspect he just used a 10k potentiometer and turned the wiper until he had the bias right, and then measured the resistance on each side of the wiper.

Some times there is no math needed.

By the way - that is not the best way to drive a speaker.
 

Ron H

Joined Apr 14, 2005
7,063
I hope you understand that most of the circuits in that section are not recommended for actual use. They are just there to illustrate the principles of BJT biasing, and are not practical.
 

Audioguru

Joined Dec 20, 2007
11,248
That is the stupedist audio power amplifier circuit that I have ever seen.

If anybody wants to burn out the speaker with 0.94A DC current in it all the time, then the transistor will also burn out since it dissipates 7W.
The transistor must have an impossible high current gain because the resistor values are much too high.
 
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