> Hmmm . . . interesting. On a quick check the US Radio Shack catalog
> I don't find listings for any sort of gold finish on switches.
> I do recall an increasingly popular line of high-power automotive
> audio components sold here in the states that refers to "gold
> plating" on the contact surfaces. I've ordered in some of these
> devices (fuse holders for the medium size cartridge fuses) and
> I'm a bit suspicious of the nature of the plating. It's a super
> glossy finish . . . not unlike the gloss you see on "chrome" plated
> plastics which is indeed an aluminum finish. Knowing what I
> pay to have gold added to etched circuit card fingers and comparing
> the price of plated versus non-plated fuseholders, I'd sure like
> to know what the finish REALLY is . . .
RS is the UK Radio Spares Components. A very large (and expensive) catalogue
supplier. I will order one of the switches (they have an NZ branch) and do a
bit of exploring and let you know.
> Now, if you really wanted to weld some switch or relay contacts, DC
> is going to be the prefered weapon . . . AC goes through zero-volts
> every few milliseconds . . . the arc fires tend to go out and not
> re-light.
>
I used to have that problem on DC operated computer tape drives where they
switched the motor power with relays. The catch was that they used current
reversal to rapid stop the drive (brutal!!) and every so often you would get
I relay that would flash overand weld. With the right combination of sticking
relay you could get a really effective Rewind and Snap Tape effect!! I used
to spend at least one day a week cleaning relay contacts to remove pitting
and build up. Thank goodness things have advanced a little since then!
> /The RS ones are rated to 10A DC but ditto.
>
> I'd like to see one of these too . . . Miniature switches on this side
> of the pond tend to be on the class of C&K 7000 series toggles.
I will get you some samples this week and send them up to you.
> If we've done our homework and depend upon no
> single system for comfortable completion of flight, then FLIGHT SYSTEM
> reliability is not compromised by a slight reduction in the reliability
> of a single lighting system, etc.
My instructor hammered into me the ability to do a landing without reference
to any instruments just in case it happened to me one day. The one thing I
prefer to keep running is the big cooling fan up front!
>
> /Its also a hell of a lot easier making round holes that it is
> /making square ones I can tell you!!
> You got that right. BTW, are you aware of a cutting tool called a
> "spot facer"? These are intended to produce smooth, perpendicular
> bolt, nut and washer surfaces on irregular or rough shapes. They
> are available in many sizes and use a pilot hole to guide on. Used
> in a hand drill they cut VERY nice holes in sheet metal. The don't
> snag and rip through like a twist drill. I'll be stocking 1/4" and
> 15/32" tools when our website catalog gets up and running. Use
> one of these once and you'll never go back to the old way.
I will buy one of these. They sound really useful. Having drilled over 300
holes in my last railway control panel - all in straight lines - anything
that makes hole preparation easier is worth the money.
P-channel devices are looking quite good too . . . some
> now below .02 ohms in the higher current ratings. These can be used
> "upside-down" with source attached to bus and you pull down on the
> gate with your low current switch. . . . . This is a VERY practical
> alternative to relays . . . no open contacts to corrode, weld, wearout,
> etc. . . . I'm planning some articles on the subject . . probably not
> until next fall.
Looks like I will have to dig my breadboard out and have a play. I haven't
played with these devices yet.
Got lots of things on my plate for the summer and through OSH.
Not the least of which seems to be spending half a day reading email :-)
Nice to chat with you again.
Can you give me your postal address so I can send you those switches.
Have a good weekend.
Tony
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Tony Krzyzewski tonyk@kaon.co.nz
Managing Director Ph 64 9 358 9124
Kaon Technologies Fx 64 9 358 9127
Auckland
New Zealand
Networkers visit www.kaon.co.nz
Aviators visit www.kaon.co.nz/europa/272index.html
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