[SOLVED] The Difference between TRAN and AC

[nature0303]

The Difference between TRAN and AC analysis

I am working with a unity gain amplifier,and i get the right result with DC analysis,but when i try it again with TRAN analysis,the out put seems too small.
Here follows the wave:



I think that TRAN analysis is based on the initial value of each node,and AC's is based on the result of DC analysis.
But how can i solve this Problem?

regard
nature

 

[goldsmith]

I am working with a unity gain amplifier,and i get the right result with DC analysis,but when i try it again with TRAN analysis,the out put seems too small.
Here follows the wave:

tranvsac.jpg

I think that TRAN analysis is based on the initial value of each node,and AC's is based on the result of DC analysis.
But how can i solve this Problem?

Hi Nature
Can you please show me your circuit ?
And did you measure the out put after transient time ? before steady state many of the events are not as they have expected to be . on the other hands we can guarantee behavior of each circuit after TRAN time . but we can calculate the behavior of tran time .
Ok now show me the circuit please .
Best Wishes
Goldsmith

 

[nature0303]

Hi goldsmith,
It's so kind of you to reply me.
And I think i have find the answer of the problem.
Because i have carelessly set the Frequence of the input too High,so the AC output would surely be lowered.
And more importantly,I set the DC voltage of input to 0V,which should be 0.9V as a circuit of 1.8V vdd.
So,after modified the two erros,i get the perfect result.

Thank you for your analysis,and i will do TRAN befor AC to be more accuracy.