calculation how to.

[kees52]

Hi there

I am very very bad in arithmetic, I see this formulas but get doozled.

However I can not without, and as such can someone have give some tip about how to do this calculation formulas, she do work but get 0.00000762 or so what means pf in this case, we have ohms, or farads but it is easyer to get pf and uf and such.

This is for a postfeedback for a 5 level class d, I get it work and give on 1 Khz very low -100 dB but on 20k it clips, that is the trouble with postfeedback we need a good calculator, maybe there is a sofware for this like matcad but also here we need to now how to use, because that does also need deep learn.

thanks in advance.

 

[rayma]

she do work but get 0.00000762 or so what means pf in this case, we have ohms,
or farads but it is easyer to get pf and uf and such.

That's probably in Farads, so it's 7.62uF.

 

[kees52]

That's probably in Farads, so it's 7.62uF.

Thats quick thanks,.

the above tekst was a example, I now did set tekst on pic for clearance.

No i have to get 520 pF it does 490pF I think, this make calulation more difficult so a nice software to do this things are welcome.

I have a casio fx-82ms calculator, old one, but is scientific maybe there are special ones for electronics or better moderner types.

regards

 

[rayma]

the above tekst was a example, I now did set tekst on pic for clearance.

A scientific calculator should be fine, though there are many circuit analysis programs.

 

[kees52]

A scientific calculator should be fine, though there are many circuit analysis programs.

I have LTspice but can now simulate a 5 level class d postfeedback if the feedback PID is not properly calculated, it is not possible by replace parts, such time consuming.

But maybe you now more programs, have you names.?

regards