Does anyone recall those power saving "discs" for light bulbs they were
selling back during the oil embargo days of the 70's. The disc was placed
in a standard light bulb fixture and the light bulb was screwed in next.
The disc was nothing more than a diode that "saved energy" by blocking power
to the bulb for half of each cycle.

Is anyone still making these things? If so, where can I buy them?