On 9/19/2016 8:20 AM, Dan Espen wrote:
"TomR" writes:

Are circular fluorescent lights dimmable?

A friend of mine just called me and asked me this question? I told him that
I think they are not dimmable, but I am still checking.

He said someone has him putting up a flush mounted circular fluorescent
light in a kitchen ceiling, and she wants to have it put on a dimmer switch.

Nope.

Florescent lights need an internal transformer to pump up the voltage
so that the electrons can jump from one end to the other. Attempt to
reduce the power and the electrons will no longer be able to make
that jump at all. The only practical way to dim a florescent is
to put a shield in place.

GE makes dimmable circline lamps; http://goo.gl/cSNyTN The data sheet
says to write to GE for recommended ballasts.