[sdiy] Transformer confusion

[John L Marshall]

Eric,

Transformers are pretty straight forward:

Except for small losses due to; eddy currents in the core, hysteresis, copper resistance, flux leakage, transformers are efficient.

The voltage ratio is the same as the turns ratio

N-in : N-out

V-in : V-out

Power out equals power in minus the losses mentioned above.

P-in = P-out

Current ratio is the inverse of the turns ratio. Input current is a reflection of the demand on the output.

I-out : I-in

The impedance ratio is the square of the turns ratio.

Z-in = Z-out ( N-in / N-out)^2

I hope this helps.

Take care,
John

Pacific Northwest Synth Meeting September 25, 2004
  ----- Original Message ----- 
  From: Robotboy8 at aol.com 
  To: synth-diy at dropmix.xs4all.nl 
  Sent: Tuesday, September 21, 2004 4:27 PM
  Subject: [sdiy] Transformer confusion


  Alright.  I was thinking about transformers today, and have come up with a lossless passive amplifier!  (Okay, I know this wouldn't work, elsewise it would be a miracle device that everyone would have heard of... but I'm trying to figure out WHY not).

  So.  A step-up transformer - two magnetic cores with wires, yadda yadda - increases voltage, but you pay for that increase with a decrease in wattage.  (right?)  So far we have the xformer with less windings on the left and the one with more on the right.  Now get another one that's identical to the one on the right (more windings than the one on the left) and set it furthest left (so you have more-wound, less-wound, more-wound in that order).  That one will act identically to the one on the right (correct?) but be 180 degrees out of phase (correct?).  But what if you ran that through an inverter and combined that signal with the output of the other more-wound inductor, wouldn't you have a higher signal (in voltage AND wattage) than what you started with?

  I know it doesn't work this way.  What I'm wondering is why it doesn't.
         -eric 
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