[sdiy] Transfer Functions

[Stewart Pye]

Hi David,

Thanks for your encouraging thoughts. I already know Kirchhoff's laws, 
and all the general electronics laws, and am fine with algebra and 
transposing equations, so maybe I should persevere. I can see that it 
will be useful. I'll check the Library for books.


Regards,
Stewart.


David G. Dixon wrote:
>> I've realised it would be a struggle for me to learn the mathematics
>> involved. I'm pushed for time as it is and would rather spend it doing
>> something I enjoy, and that level of maths is not something I enjoy. I
>> generally understand how circuits work and know what to fiddle with to
>> change them so I should be able to get by without knowing what a Laplace
>> transform is.
>>     
>
> That's too bad, because you don't even need to know what a Laplace transform
> is to derive transfer functions for filters.  All you need are a couple of
> impedance formulas, Kirchhoff's current law, and some basic algebra (i.e.,
> equation rearranging) skills.  To draw filter response plots, you only need
> to separate the real and imaginary parts of both the numerator and
> denominator of the transfer function, square each part, add them together
> and take the square root of the sum, then take the log of the whole mess,
> multiply it by 20, and plot the result vs f or w (omega).
>
> Really, the math you need to do basic filter analysis can be mastered in
> about half an hour.  That's not really going to cut into your
> circuit-building time, now, is it?
>
>
>