Warning, this is a techie post...

I just read a post where someone was commentint on light color and dimmers, and he used the term "resistive dimmer". I don't believe I've ever seen a resistive dimmer used for lighting. The older style of dimming (used in theaters and such) was done with a variable transformer, which actually changed the voltage going to the light fixture. Most home dimmers use an SCR or Triac to change the amount of time a light is on. They don't actually vary the voltage at all, it's still 120 VAC going to the bulb, but instead of being the normal sinewave, the voltage becomes more pulsed, with shorter pulses giving dimmer light. That's why the filaments in incandescent bulbs will buzz (or ring) and why most florescent lights will flash. This type of dimmer is actually pretty easy to make -- I made several of them when I was in high school.

You just aren't old enough to remember the resistive dimmers. Variable transformers were too expensive for home use. The resistive dimmer was strictly for mood lighting and people didn't dwell on the inefficiency.

You are also not old enough to remember when the apartment got colder at night when the super went to bed and nobody was left to shovel coal into the furnace in the basement. Lucky you!

Just guessing, but I'd bet you probably made a crystal radio in high school too. Sound like a ham to me. Takes one to know one (N5CMM) 73's