11 Jul
2007
11 Jul
'07
4:12 p.m.
On 7/11/07, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
> And that 90V battery was probably the single
biggest reason why I never
> built one of those...
Me, either.
Back when I built mine, 90V batteries were still
fairly easy to obtain.
Nowadays, I'd probably go to the local 'pound shop' and buy 10 cheap 9V
batteries and link them in series. The current drawn is so low that even
cheap-n-nasty 9V batteries would last quite a time.
Certainly, that works, but I'd be curious what the lifetime would
be... years? under a year?
I would think that the shelf-life would be a significant component in
the lifetime calculation, not merely current draw.
I can see how one could make some sort of snap-together 3D battery
sculpture to make a 90VDC brick, but would doing so create some sort
of safety issue? (discounting grabbing the most negative and most
positive terminals thereby attaching yourself to 90VDC - that is an
implicit safety issue that would still be there if you could find an
old 90V dry battery).
IMHO it's cheating to use a step-up switching
regulator IC. If you've got
one of those, you can get a 555 timer ;-)
There are plenty of 1970s designs for those - I have them in the Sams
"555 Timer Cookbook", and, I think, in "Don Lancaster's TTL
Cookbook"
(he dips into 555 designs as they interface to TTL circuits). I don't
think there are any listed designs that go up that high there, but
extending what's there isn't too difficult. One doesn't need a 90VDC
1A power supply for blinking nine neon bulbs.
I may have to dig around my junk box for some bulbs...
-ethan