Re: Interfacing to AC; lamps, relays

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "D.C. Cox" <resonance@xxxxxxxxxx>



No, reverse diode if he is running DC which is better --- less chance 
of spikes due to more filtering of PS.

Dr. Resonance
----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Monday, October 31, 2005 4:54 PM
Subject: Re: Interfacing to AC; lamps, relays


> Original poster: FIFTYGUY@xxxxxxx
> In a message dated 10/31/05 1:09:39 PM Eastern Standard Time, 
> tesla@xxxxxxxxxx writes:
> Original poster: "D.C. Cox" <resonance@xxxxxxxxxx>
>
>
> Use a .01 uF cap across each relay to absorb this kick and also a
> reverse diode to block any additional kick.
>
> Dr. Resonance
>
>
>     "Reverse" diode for an AC relay coil?
>     IIRC varistors do a better job than the R-C snubbers. The R-C's 
> have to be carefully tailored to the coil 's properties to do much good.
>
> -Phil LaBudde
>
>
>
>
> >     What I would like to do is interface an 8255 PPI chips
> > (essentially, three 8 bit I/O ports, programmable) to several things:
> >
> >     A: 24 volt AC relays. I am especially concerned about the
> > inductive "kick" that's going to happen when an energized relay
> > opens. (If necessary I can set these up for DC, but I happen to
> > have a lot of these relays at this voltage).