# Analysis of circuits towards stability

## Main Question or Discussion Point

analysis of circuits towards stability ....

I studied so many materials and some of those are describing about analogue corcuits for many purposes. In part of that everytime they explaine about pole ZERO concepts(whenever i seen those words in paragraph i feel that is bad ). I need to overcome that by your help.

First of all if you are designing any system which mixed up with analogue circuits. how can i decide myself and analyze after seeing that circuits(like that resistor will cause for dominant pole or may be it can make zero) like you are analyzing now.

Dont say me like you need to draw bode plot for that system. tell if there is any shortcuts. and how you are analyzing circuits by telling those points. how can i improve in that area..

need any suggestions to analyze the circuit.

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I studied so many materials and some of those are describing about analogue corcuits for many purposes. In part of that everytime they explaine about pole ZERO concepts(whenever i seen those words in paragraph i feel that is bad ). I need to overcome that by your help.

First of all if you are designing any system which mixed up with analogue circuits. how can i decide myself and analyze after seeing that circuits(like that resistor will cause for dominant pole or may be it can make zero) like you are analyzing now.

Dont say me like you need to draw bode plot for that system. tell if there is any shortcuts. and how you are analyzing circuits by telling those points. how can i improve in that area..

need any suggestions to analyze the circuit.
I'm barely understanding your question. I also don't know what you know about circuit analysis, control systems theory and the math of both. What do you know about:

• Complex numbers and complex algebra
• Circuit analysis techniques
• Transistor circuit design
• Control systems theory and stability

If you know these already, then don't take it as an insult; I need to know "who" I'm talking to technically answer your question without wasting your or my time. The answer will start with the above areas of knowledge.

In practice, you would have internalized/learned the above (which includes Bode Plots but other stability criteria as well) and then only with practice do you reach a point where you can say "by inspection" (just by looking at the circuit) how the bandwidth or stability might be affected. Strictly you are still going to write out some equations and do some calculations to be sure.

Something as complex (no pun intended) as stability usually can't be done "by inspection" visually. You really only can go through the work of analysis. Folks who do analog design have simply done it some many times that we make it look easy. It's not.

I don't know of any shortcuts to anything in life that actually work.

Poles are where the dependent variable goes to infinity. Zero's are when it goes to zero. That's all.

The independent variable is complex, so a pole is just some place on the complex plan where the independent variable goes to infinity.

Some pictures. http://www.chem.mtu.edu/~tbco/cm416/PolesAndZeros.html" [Broken]

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