I have track lighting in my kitchen with three lights on it. I recently put
in some of the flouresent bulbs that fit in incandesent sockets, thwy work
fine. However, I have noticed that after I switch the light off, the middle
light will flash every 5 seconds or so. And only one tube of the flouresent
The only thing I can think of.. ( a long shot) is that I had installed a new
swith that lights up when the lights are switched off. Somehow some
electricity is getting to the light through the switch. But Why only one
tube of the light. I have yet to get up there with a meter and do some
testing. I'll post the results
Not so long a shot.
Turn off lightswitch. Unscrew all the lights. Does the switch still
light up? Probably not.
The little neon bulb in the switch has something like a 90,000 ohm
resistor in series with it, and this series combination is in turn in
parallel with the switch contacts. When the contacts are open, current
flows from the hot through the neon bulb (making it light up), through
the 90K resistor and through the 12 to 500 ohms worth of lighting
equipment (typical 25 to 1000 watts incandescent) eventually to
ground. If you remove the load (unscrew the lightbulbs) then the
circuit is no longer completed and the neon should go out. (Sometimes
capacitance in the wiring allows the bulb to glow a bit even if
there's no load.)
Converse is that when you turn off the switch, a small current still
flows through the neon bulb into the load. This probably slowly
charges a capacitor in the electronic ballast in the compact
fluorescent bulb(s). When the capacitor voltage hits a threshold, the
ballast "thinks" it's being powered and tries to start the bulb. The
capacitor discharges because the current flowing through the neon is
insufficient to power the ballast. Then the cycle repeats.
Make sure one of your bulbs is incandescent and this problem will
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.