bad layout

[Hairy Harry]

Hi all...

Bad layout is the quickest way to destroy a circuit short of:
designing one that will never work... or
plugging it into high voltage...

The problem is that none of the elements of a circuit are perfect,
or exist in a world of their own.

If you take a microphone and put it in front of a loudspeaker...
bad things happen.  Same thing happens when the output of a circuit
is too close to the input... things like stray (unwanted, often
unaccounted for...) capacitance, inductance... couple the circuit
just as surely as if you took extra components and soldered them in
where they do not belong...

If you run microphone cables along side power cables for stage lighting, you 
usually get a hell of a hum. This is caused by stray
capacitance, inductance, magnetic fields, etc.  Most people know that
the best thing to do is "don't put those cables together"... Even
running them in steel conduit might not work as well as separating them by a 
few feet.

Careful layout is a must. You might get lucky and find a good layout
by accident. Or if you are laying out a flashlight or similar circuit
where you just don't care... you will be OK.  But usually high gain
audio circuits (like VCA, VCF, etc...) if you have problems they WILL
bite you in the @ss...

H^)  harry


>From: Ingo Debus <debus at cityweb.de>
>To: synth-diy at node12b53.a2000.nl
>Subject: Re: tr-909 schem's
>Date: Sun, 29 Oct 2000 11:32:22 +0100
>
>
>
>Alan Podjursky wrote:
> > I don't quite get how bad layout can affect a circuit, so I plan on
> > ignoring that part for the moment :-)
>
>Simple rule: you can prevent any circuit from functioning properly if
>the layout is bad enough...
>
>;-)
>
>Ingo
>
>

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