[Amps] PS Theory ?

[Ian White, G3SEK]

rlm wrote:
>***  Approximation formulae are given in:
>http://www.somis.org/D.amplifiers.2.html
>The math is multification and division.

Those really aren't approximation formulae. They are handy practical 
rules of thumb that often will work... but sometimes won't.

Please don't get me wrong on this. Anyone who is contemplating a 
transmitter power supply ought to read Rich's page on the subject - see 
above. By all means use Rich's rules of thumb to check the transformer 
and other components that you're thinking of using... and if they don't 
check out, then it's "STOP. WRONG WAY. GO BACK" and find other 
components.

But those rules of thumb still won't tell you exactly how those 
components will perform in practice. The 'PSU Designer' program *will*

The kinds of power supplies we're talking about here in AMPS are big, 
heavy and expensive. And when you build one, you are very literally 
building it around the transformer. If that transformer isn't suitable, 
you're almost certainly going to need a bigger one that will not fit 
into the same space. That means you'll have to scrap the whole darn 
project and start again. If the project is not only a power supply but a 
complete desktop amplifier, then you've wasted even more time, money and 
effort.

Having suffered exactly those disappointments in the past, it certainly 
"cured me of my gambling ways" with transformers! I now want to be 
absolutely sure it's going to work, before going out to the workshop. 
That's why I so strongly recommend 'PSU Designer'.


-- 
73 from Ian G3SEK         'In Practice' columnist for RadCom (RSGB)
                            Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek