switching at zero cross/noiseless switching

[John Speth]

Aside from the arithmetic elements of the problem, I seem to remember that 
the switching devices have show some charge injection when switching 
occurs.  For example, even if both ends of the switch are at the same 
voltage, you'll still get a click.  Maybe a good design can minimize this. 
 I can't remember where I read this though.  Does this sound familiar to 
anybody?

John Speth
Object Engineering, Inc
mailto:johns at oei.com