# circuit biasing

Discussion in 'General Electronics Chat' started by srinivasan01, Mar 14, 2010.

1. ### srinivasan01 Thread Starter New Member

Jan 16, 2010
8
0
hellow friends once again,
can any one breaf me about the proper biasing to circuit.
how to choose the value of resistor ,capacitor etc...............
when to choose isolation & ohter transformers.
where to start from & where to end througt the circuits..........

2. ### hgmjr Retired Moderator

Jan 28, 2005
9,029
218
Can you provide us with more details?

hgmjr

3. ### srinivasan01 Thread Starter New Member

Jan 16, 2010
8
0
hai ...
may be a oscillator circuit of your own or standard one & tell me about the biasing about in that circuit.
just give me the basic knowledge of biasing and then i will ask in detail about them.............
hope you understand my position........

4. ### Audioguru Expert

Dec 20, 2007
11,091
1,289
You need to learn about electronics and transistors to be able to design a biased transistor circuit. When you know the basics then the datasheet of the transistor lists all its spec's and simple arithmatic is used with simple formulas to calculate the parts for biasing.

5. ### Mike33 AAC Fanatic!

Feb 4, 2005
349
25
For example, let's say you are using an electron tube. You have looked at the graph of its characteristics from the data sheet. You determine you need to bias the grid at -2V for proper operation along the curves that show the device's operation. You then select a resistor that will make the cathode 2 volts MORE POSITIVE than the grid, and place this at the cathode of the tube. This is done by determining the current that will flow through the tube (or transistor, etc.).

What this "biasing" is doing is establishing the 'reference point' for an incoming AC signal. It is the point that the signal will rise above, and fall below, often shown as zero or the X axis in mathematics class but for real devices and power supplies, we need to establish that reference point within the parameters the device can operate on. If you don't bias something correctly, parts of the wave will be cut off or distorted, among other things.

As stated above, look on Google for "transistor tutorial" and you will find everything you need to begin learning! )