Tony and museums (was Xerox Alto..)
ard at p850ug1.demon.co.uk
Mon Oct 18 14:17:27 CDT 2010
> On Sun, 17 Oct 2010, Tony Duell wrote:
> > Often the 'high beams' are known as 'main beams' over here. As opposed to
> > 'dipped beams/headlights'. The swtich to select between them is the
> > 'dipper switch' or 'dip swtich'. The original (trade?) name for a twin
> > filamanet headlight bulb was a 'double dipper'.
> > Incidentally, what word would you generally used for 'dazzled'?
OK... That's also said over here, but normally as slang rather than
written in manuals.
> Unfortunately, the lack of differentiation between "flash blindness" and
> permanent damage has led to many people believing that thousands of people
> have permanently lost their eyesight due to laser pointers.
> In USA, it is called a "dimmer switch" and "dual beam", and high beams are
As I understnad it, the original anti-dazzel device for electric
headlamps was a rheostat (variable resistor) to dim them. This was
replaced by a mechancial dipping system, when you pressed the dipswitch,
the RH (nearest the centre of the road/oncoming traffic) was turned off,
and the LH one was moved mechancially by a solenoid. Then came the
twin-filament design whcih is, of course still used on most cars today.
So the original really was a 'dimmer'.
> NEVER called "main", possibly due to the likelihood that the clueless will
> misinterpret that to mean that they should almost ALWAYS be in the "high"
> The filaments in a dual beam "sealed beam" headlight are not individually
Sealed beam headlamps (large glass envelope incorporatign the reflector
and front lens) have fallen out of fashion oer here. Most cars have a
reflector/lense assembly (often approximately rectangular) with a
twin-filament bulb inserted from the rear. Often these days it's a
tungsten halgoen bulb. when it fails, you replace just the bulb. But of
course you do have to replace both filaments together.
Actually, my father's current car, a Skoda, has separate tungsten halogen
signle filament buibs for the main and dipped beams. So you only have to
rrplace the filament that's failed.
> replaceable. If you can intercept one being discarded, the use of the
> remaining filament makes it a very handy load for power supply testing.
Indeed. Of coruse part-failed twin filamanet bulbs are good for this too.
You normally have to specially order them, but 6V car bulbs are
available. A 6V headlamp bulb will typically have a couple of filaments
rated at 30-odd watts each. Which make ideal loads for large-ish 5V
supplies (put both in parallel for a 10A or so load). The 6% 5W tail lamp
bulb is good for smaller supplies.
> The dimmer switch is now on the steering column in a multi-purpose
> combination switch that controls enough things that it is not generally
> considered to be repairable, in lieu of replaceable.
Sme over here. Actually, most of those multi-function swtiches can be
taken apart, contacts cleaned, etc.
> I remember when the dimmer switch was a button for the left foot.
I;'ve never been in such a car, but I've got plenty of books describing
them. A friend of mine drives a car where the (oriignal equipment)
windscreen washer pump is on the floor, left foot operated.
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