One thing to remember is that a transformer will pass certain AC junk along with a pure sine wave. It won't filter noise from AC mains. If it's a step-down transformer it will step down any noise too, but the noise will pass through. Any change in voltage on the primary is reflected into the secondary at the level dictated by the turns ratio of the primary to secondary.
Agreed. Any out of phase signals introduced by the noise will be attenuated on the opposite swing of the 60 Hz sine wave of the primary voltage, but that's a very complex waveform. Won't that noise be riding on the 60 Hz (or 50 Hz in Poland, maybe)? If I'm understanding Lee correctly, the fan outlet is in parallel with one half of the transformer primary when it's configured for 240 VAC. In addition to your analysis of the transformer load, the fan, tapped across the primary as it is, effectively makes the primary into an autotransformer. It behaves like a variac with a permanent tap instead of brushes. Then the secondary draws from that load. Like you said, there is current division in the primary, so any noise is introduced in that half of the primary. This is where I start to lose it and need to go do the math. Now, (and this is a guess) since the fan is going to draw around 25 watts, maybe 200 mA @ 120 volts, won't any noise generated be inconsequential? Before it makes it to the audio It has to get though the transformer's secondary inductance (and i'm just tossing that around as an unknown that may or may not be of consequence) and then through the power supply rectification and filtering.
We love getting down in the WEEDS don't we?
and then there was a black hole called GROUND LOOPS...
We love getting down in the WEEDS don't we?
BTW, went to see the movie "AMERICA" by Dinesh D'Souza today. Fantastic movie...it makes you proud to be American again. It examines the lies of that those who would have us believe that America was built by ill-gotten means in a factual, historical look at our country's beginnings, maturation, and future.
An eye opener...for example, the first female millionaire in America was an African-American woman who started her own cosmetics company and sold her stuff door to door. It shows us the benefits of capitalism and talks about the American Dream. It's roots, and the realities that it faces in today's world. I left the movie feeling positive and informed. Very well done.
I don't care what your political affiliations are, this movie is a must see for those of us who are tired of being fed propaganda from BOTH SIDES OF THE AISLE. USA!!! USA!!! USA!!!
And happy belated Independence Day, everyone!
