# Teaching transistor Biasing

#### joejoenikk

Joined Nov 23, 2011
9
I've been looking for on line lessons about transistor biasing that make sense for some time now. There are a lot of them out there, but few that are actually useful.

Today I found one that was wonderful, until I got to the "useful" part. The online instructor was from a Japaneese electronics/College and as usual, he forgot that I might have intentions of learning from online instructions for the purpose of actually applying the lesson and like most students don't have anyone to help. His lessons were great, for example he taught that transistor biasing uses basic algebraic tricks and Kirchoff pretty much wrote the book on the algebra short cuts. When I got to the page that I need about voltage divider biasing, I though I had it made, he covered the fact that I had selected the correct biasing method, voltage divider bias allows me to run my project's transistors at a known, fixed gain, but he never explained the practial uses of the other types of biasing. After I spent a few hours working on his math, The instructor hadn't bothered to write it but by accident, I had learned that there is a form of shorthand that involves starting at the nine o'clock position of a schemetic, and from ther clockwise reading/writing/drawing the mathematics/schematic and writing the componet's values. When I read again the section on Voltage divider biasing, guess what!!! after looking over the mathematics for another half an hour and as well as I could, he never provided any method of algebra for starting with a known intended gain and ending up any closer to the correct parts to build it.

If one of you guys want to start with a description of what the type of baising is usually used for and realise that "the easy awnser", for me doesn't involve marrying an algebra teacher or changing my curriculum to another copy of another teacher's work, like most people who read college lectures on the web, I'd be intrested in reading the lecture. My current "curriculum" involves my being buisy learning that I went out and got a job because I couldnt afford to go to college, but I'd hate to change it to sitting in front of the telivison and wasting my mind.

#### k7elp60

Joined Nov 4, 2008
562
If I understand you correctly you are trying to figure the values of the resistors for a transistor biased like this circuit(attached). If so I would be happy to teach you how to figure the values with simple math.

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