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...
On Sat, 10 Nov 2012 00:28:53 -0500, "tm"
wrote:


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On Fri, 09 Nov 2012 21:30:28 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

"tm" fired this volley in
news:k7khim$at3$1
:

Well, if it has a poorly designed triac controller, it may radiate
RFI.

Even well-designed ones do on the turn-on. Only a lot of down-line
choking and shielding will get it down to reasonable levels.

But it's not likely that the RFI emitted from a 1/2-amp controller would
emit enough to be harmful to tissue. Could screw up your pacemaker, I
guess...

Lloyd
There ARE controllers that switch on the downward slope of the sine,
greatly reducung theRFI.

One thing for sure - an electric blanket sure plays havok with
magnetometers, like in electronic compases - and electronic gyros.

It's best when they switch on the zero crossings.
Which means either full on, half on, or off.

So? You don't need a per cycle control. On-off every minute would be fine.
Or % of a minute.