Samuel M. Goldwasser wrote:
"William Sommerwerck" writes:

As the strike voltage is higher than the sustain voltage, you should
be able to turn down the dimmer a bit. However, I suspect the lamps
won't get dimmer -- rather, less of the flame area will be illuminated.
I`m not interested in dimming them, just being able to make them strike
with a rising voltage
???

but does the voltage vary much on a domestic dimmer? Will it drop below
the neon's sustaining voltage? There will be other normal filiament lamps
in parallel with the flicker lamps.
I'm not sure what you're talking about.

There are two types of dimmers. (Maybe more, but I only know of two.) One is
a variable resistor (or better, a variable transformer) that actually
changes the voltage across the load, either by introducing series
resistance, or changing the source voltage itself. As these are bulky and
not cheap, they are not generally found in homes.

The other type of dimmer -- of which the X10 is the best-known example --
uses an SCR or triac to vary the duty cycle of the AC. The SCR is "off"
until the AC waveform reaches a certain level, which is set by the knob,
slider, etc. The SCR remains "on" until the waveform drops to zero, at which
point it shuts off. The later in the cycle the SCR turns on, the less energy
is delivered to the load. * Incandescent lamps are sufficiently thermally
sluggish to smooth out the variation, and there is little or no visible
flickering.

In such a system, the peak voltage is _always_ the full line voltage, with
the amount of energy delivered to the load controlled by how much of each
cycle passes through the SCR.

Once you turn the knob to the point where the SCR triggers, you will always
have a peak voltage of about 170V (on a 120V line), which, in principle,
would make the neon lamp strike.

But how the lamps behave, and what you see, is not clear (to me). You're
just going to have to try it and see.

* Don't put a dimmer on a tungsten-halogen lamp, unless you limit its use to
setting the light at a low level. If you set it a bit below peak, the
filament will be hot enough to burn out prematurely, but not hot enough for
the halogen-recycling process to be effective. Yes, I've seen this happen.

99.9999999 percent of common dimmers use a triac to turn on the load
at a point in both the positive and negative portions of the AC cycle
determined by the brightness setting. It turns off when the current
goes to zero.

For high brightness, it turns on early in the cycle.
For low birghtness, it turns on late in the cycle.

However, with a gas discharge lamp, the load is an open circuit until
it strikes and is a very high resistance load even when it is running.
The dimmer is a two-wire device which depends on the load to draw some
current at all times and provide internal power to the dimmer.

I would expect a neon lamp to work but for the dimmer to have little or
no adjustment range.


Then that`s exactly what I want, when the house lights go up, the
flicker lamps strike, and when they go down, off they go. I`m just
hoping that the voltage across the neons when the dimmer is on minimum
is low enough for them to unstrike. There will be incandescant bulbs in
parallel with the neons, so the dimmer sees a load anyway.

cheers

Ron