Mark Lloyd wrote:
On 29 May 2007 14:47:45 -0700, dpb wrote:


On May 29, 11:06 am, "CooSer" wrote:

I am a little baffled. I have flood lights that used to work. They stopped
working so I replaced the bulbs with indoor/outdoor type flood lights. This
did not fix the problem. I checked the sockets with my little $6 voltage
detector and there is power. In fact, there is power in the sockets whether
the switch is on or off.

Now could it not be working because I need a special 'Outdoor' bulb? Or,
since I get a power reading with the switch on or off, is there something
wrong in the wiring?

What type is your tester? Is it an inexpensive volt-meter or a neon-
bulb or similar? If the former w/ a needle indicator it's quite
possible as Jeff says the voltage is phantom. If it is a indicator
light type, and the light is being lit, then the voltage is real and
the problem is twofold...

If you don't find the problem first, post the answer to the question
and I'll not start a tome on what else to look for...

Although I will ask -- is there more than one location from which to
turn the lights on/off from? It's possible the other switch is the
problem of voltage.

Also, if there is real (not phantom) voltage, and the light doesn't
light, then the problem almost certainly has to be in the base--either
dirt/corrosion or perhaps the base tab has become flattened to where
the bottom of the bulb isn't making contact.


Any voltage you can measure is a real one ("phantom" doesn't make
sense here, meters measure real voltages only). What's different is
the source impedance (the effective resistance of the source, which
determines how much the voltage drops with load). When dealing with
power, you want a LOW source impedance, so the load causes very little
voltage drop. With a very high source impedance, the load causes the
voltage to drop too low to light the bulb.


But, I'd say first guess of reading a impressed voltage is probably
the most likely culprit...


Yes.


Don't quibble with just me Mark. NEMA recognizes "phantom" as a term
too: G

http://www.nema.org/stds/eng-bulleti...ulletin-88.pdf

Jeff



--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.