On 8/2/2014 9:45 PM, Martin Eastburn wrote:
On 8/2/2014 9:18 PM, Lloyd E. Sponenburgh wrote:
Martin Eastburn fired this volley in
:

If you can see the change it isn't the filament drawing current.
Martin


Just the opposite, Martin. An arc strikes and quenches
instantaneously (up
to several microseconds really, which isn't actually instantaneous,
but it
would appear to be to the human eye). Only a filament's heating and
cooling would cause a visible ramping in brightness up and down.

Lloyd

I don't buy it Lloyd You claim you can see a light bulb start to glow
and then light and then when shut down the glow goes down in stages ?

If the filament was being heated by an arcing across plasma stream it
would ramp up in real time and could be seen. Either as a broken
filament or across the 'skin' of the tungsten which heats up the filament.

I have a degree in Physics and 20+years as a EE. A heating filament is
simply to fast to see and the eye integrates the changes.

Martin

You can certainly see a filament ramp up at lower voltages, I think we
have concluded that the filament has lower voltage on it.

Another explanation would be, the filament is there but open, the arc
jumps across and heats the filament and there is a lag to heat it to
glow and then a lag to cool and reduce the glow.
Mikek