AW: AW: [sdiy] precision/matched capacitors??

[Magnus Danielson]

From: Czech Martin <Martin.Czech at Micronas.com>
Subject: AW: AW: [sdiy] precision/matched capacitors??
Date: Fri, 2 Nov 2001 16:32:09 +0100 

> That's true. They even bake their circuits to get some
> pre aging. Which cold also be a way to settle a vco.

Interesting indeed. It is also interesting to consider what residues
one leaves on the board. If you clean them off proberly and then mount
them so that they is not exposed to various combinations of feums,
dust, coffie, coke and beer, ie. you place it inside a closed box,
then you have a greater confidence of long term aspects... if you also
remember to keep it cool enougth :-P

> The airgap really only works if it is dry.

There are many sides to comgaps. Better onces are sealed, so that you
have a controlled environment. Those will lit in about 3 ns. If you
want quicker responce you have to pre-ionize the gas, which you do by
radiation :-P

If you are handling a balanced signal you either want three signle
gaps (two to earth and one between the sides) or a balanced gap. What
you don't want to happend in a balanced circuit is that one of the
signal-to-ground gaps lit, but not the other. This would convert a
common mode overvoltage into differential mode overvoltage. The
balanced gaps have the added benefit that is one side lits, it helps
to lit the other side.

There are many sides to spark arresters, and there is also good books
on overvoltage and overcurrent protection.

Cheers,
Magnus