On May 29, 2006, at 5:18 AM, Gerhard Fiedler wrote:

> Darren Gibbs wrote:
>
>> In my case, with a bunch of solenoids spread out over a fairly large
>> area, wouldn't it make more sense to use a PNP transistor and  
>> switch the
>> +V side instead?
>
> Why do you think it would make more sense?

I was thinking that having +50V on the wiring out to the solenoids  
and back all the time was in some sense less safe.  Switching the +V  
side would mean the network of wires is dead except for the few  
milliseconds during which they're energized to activate the  
solenoid.  I just wondered if there were other reasons for using NPN.

thanks,

darren


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