[sdiy] (OT) help with DEC branded relays

[harrybissell]

I agree...  BIG mercury relay would be perfect for small AND
large signals... unless you have enough current to start an arc
like the old Ignitron tubes !!!

RoHS be dammed, eh ???

H^) harry

The Peasant wrote:

> Quoting Harry Bissell Jr <harrybissell at prodigy.net>:
> >
> > A wide current range relay should be unnecessary as
> > the
> > current will 'sometimes' be quite high and this will
> > maintain the relay contacts.  (so - disagree here ;^)
>
> Well, for a small NAD amplifier, you are probably correct. I really don't like
> relays in the speaker circuit, although the speaker must be protected somehow.
> However, I do have some big mercury types that should work great!
>
> > Most relays are specified for switching current, not
> > carry current.  This relay is not required to switch
> > while the signal is applied.  We can also look at the
> > duty cycle of those high current peaks.  If they were
> > 10% of the time, you could multiply the actual current
> > by the square root of the actual duty cycle and get
> > the rating you require. The relay contact could be
> > rated at
> > roughly .316 of the applied current (a one amp relay
> > could carry 3 amps at 10% duty).  Real crest factors
> > are MUCH less...
> >
> > ...unless they were mastered for maximum loudness :^P
>
> Thanks for the clarification, Harry!
>
> Take care,
> Doug
> ______________________
> The Electronic Peasant
>
> www.electronicpeasant.com