I saw a commutator device in some forum to lower frequency.

[tarakan]

I saw a hand-drawn circuit on a graph paper somewhere on this forum that depicts:

• a way to rectify high frequency electricity or to turn it into 50/60hz AC
  
• it used a transformer where one of the windings was shorted by a mechanical commutator
  
• two other windings were in series with the input and the output of a driven load

Help me find this circuit diagram please.