Re: Electronic Transformers

[Richard Malcolm-Smith <rich@xxxxxxx>]

> I just noticed in one of my catalogues...
> They have various electronic transformers such as
> 20-60W  & 35-105W
> in mentions that they are suitable for Hard Fired Triac
> Dimmers
> subject to a MINIMUM LOAD of 50W per transformer

Hard fired means that the triac is forrced to turn on. normal dimmers
dump a capacitor into the triac and rely on the current flow starting
immediatly holding the triac on. All Hard fired triac dimmers use a
neutral connection.1

> Also a few years ago when I was dimming neon and
> flourescent
> lighting it suffered from instability at low levels.
> By adding a resistive load across the dimmer ( I used a 60W
> bulb)
> it completely cured the instability. You also knew when the
> bulb
> had blown as the neon went crazy again :-))

The incandescent light is purely resistive so the current does flow
immediatly making a hard firing one redundent :) - I had a problem
dimming fluros in that the fluros were nearly completly off but the
incandescent was only at 70% or so of brightness. I cant find any hard
firing dimmers except some megabuck ones for 1000 watts+ of load.
Typical residential dimmers available here in NZ have no neutral (They
are also crap, but thats another story)

--
Richard
IHUG helpdesk

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