On Mon, 20 Sep 2004, Dave VanHorn wrote:

> At 10:36 AM 9/20/2004, Falcon Wireless Tech Support - KF4HAZ wrote:
>
>> How about having it switch 5 volts or less at 30 amps or more?
>> At 5 volts the body's skin resistance would provide sufficient protection,
>> and a 30 amp or larger load would produce enough arcing.
>
> No real arc there, and no way to get a really impressive one anyway.
> You'd need a lot of inductance, which means there really would be high voltage there during the disconnect..
> Nope, some things are better when added in post.

Think of it the other way around: you want the sparks in the dark when you 
connect. When you disconnect the lights will be on anyway and the sparks 
hard to see. So a huge capacitor from surplus directly in parallel with 
the knife switch should provide a satisfying bang and spark on make. It 
would also provide turn off delay ;-) Shorting a 10,000 uF 24V cap is 
always impressive (has about 3 Joules). You could provide a second, 
disconnect bang, if the knife is the switchover type, with a second cap. 
The best effect is obtained with the spring-action knife switches (you 
can't switch them over slowly - this is to prevent arcing - and they make 
quite a bang even without power).

Peter
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