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Old June 8th 07, 01:56 PM posted to alt.binaries.pictures.radio
Brenda Ann Brenda Ann is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 855
Default Stewart-Warner reactance dimmer


"John Byrns" wrote in message
...

Interesting stuff... snipped for brevity.

I'm a neophyte to this circuit, but let me posit a thought.

Perhaps the fact the secondarys being wired in bucking fashion has not as
much to do with the function of the circuit itself as to assist in the
prevention of the AC filament voltage from being introduced into the plate
supply for the 1st. detector and 1st. IF (otherwise it seems to me it would
make a rather effective modulation transformer). Also, it seems to me that
I've seen other radios (if not the specific circuitry therein) that had
tuning lamps that dimmed when tuned on station. I can think of a couple
reasons for this. First and foremost, more light is needed when tuning
across the dial than when on station. Also, this would tend to cause the
dial lamp to last a considerably longer time than normal, since when on
station it would be running at a fraction of it's normal voltage.

On the other hand, when DC saturates the secondary, wouldn't that tend to
make the primary look like a direct short?