"Jeff Wisnia" wrote

"40 or 50 volts is enough to make incandescent bulbs glow.
Are the bulb loads connected, and if so, do they glow?"

At full ON the bulbs are very bright. As the toggle lever
is moved toward the OFF position the bulbs diminish in
brightness. With the lever horizontal (i.e., about half way
between full ON and full OFF) the bulbs have dimmed
sufficient that one can barely see the lighted filament
inside. Moving the lever farther toward the full OFF
position results in that barely lighted filament appearing
to disappear. However, I wonder if, at 48-50 volts, the
filament is hot enough to be visible through the frosted
bulbs.

He also wrote:

"If the loads aren't connected I'm guessing you have a
limited knowledge of electronics and are probably measuring
the output of those dimmers with an electronic (digital)
voltmeter which is responding to miniscule leakage currents
that give you what's known as "phantom" voltage readings."

True, I have a limited knowledge of electronics. The output
was measured with a (medium priced - perhaps $40 from Sears)
hand-held digital voltmeter, as follows: Line voltage of
110? AC was on one side of the dimmer switch. At full ON
the voltmeter read something like 116 or 118 volts. As the
toggle lever on the switch was moved from full ON to full
OFF the reading on the voltmeter dropped from 116 to 48 or
49 the first time we measured it. Second time it went to 50
volts at full OFF. I don't understand what you mean by
"responding to miniscule leakage currents ... 'phantom'
voltage readings." Are you saying that what we observed is
an artifact of the measurement device, and that in fact
there is no voltage flowing through the switch in the fully
OFF position? That would be comforting in one sense about
no safety hazard with the wiring beyond the switch, but
disturbing in the sense of never being sure whether the
voltmeter is accurate or not.

Any further elaboration/clarification you (or others) can
provide would be appreciated.

Thanks.

========================

"Jeff Wisnia" wrote in message
et...
CWLee wrote:
My son recently replaced two wall on-off switches with
dimmer switches, new from Home Depot or Lowe's, for me.
They work fine and control incandescent lights. He
discovered, however, that even when completely off about
48-50 volts still flow through the new dimmer switches -
both of them.

We are both puzzled. We assumed that off would mean
zero
volts. If this is normal isn't it a safety hazard?

Any insight appreciated.


40 or 50 volts is enough to make incandescent bulbs glow.
Are the bulb
loads connected, and if so, do they glow?

If the loads aren't connected I'm guessing you have a
limited knowledge
of electronics and are probably measuring the output of
those dimmers
with an electronic (digital) voltmeter which is responding
to miniscule
leakage currents that give you what's known as "phantom"
voltage readings.

If connected bulb loads "turn off" OK, fughedit.

HTH,

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
"Rudeness is the weak man's imitation of strength."