Tony and museums (was Xerox Alto..)

[Tony Duell]

> 
> 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'?
> 
> "blinded".

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

Interesting...

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"
> position.
> 
> 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.

-tony