TTL computing

From: Tothwolf <tothwolf_at_concentric.net>
Date: Wed Apr 10 22:36:17 2002

On Wed, 10 Apr 2002, Doc wrote:
> On Wed, 10 Apr 2002, Roger Merchberger wrote:
> > Rumor has it that Fred Cisin (XenoSoft) may have mentioned these words:
>
> > >> Anything beyond a size of several bytes would be unmanageable, of course.
> > >> I figured you might fit 64 bytes in the size of a VHS tape if you use
> > >> small fuses.
> >
> > Maybe more with picofuses, but they'd be hard to change [see below]
>
> How about the newer blade-type automotive fuses? You could use large
> fuse blocks, and they tend to "color up" a lot better than glass fuses
> when they blow.
> I can't recall seeing them at amperages <2A, though.

ATO/ATC blade fuses are available in sizes from 1A (black in color) to
40A. There are also "Mini" blade fuses available, which are about half the
size of an ATO/ATC, but IIRC, they only go down to 2A (gray in color).
Cost wise, ATO/ATC fuses will run about $25/C, while the "Mini" variety
will run about $30/C. Sockets would add more to the cost. It would cost
about $0.50/ea to mount ATO/ATC fuses to a pc board, and about $1.25/ea
for the "Mini" variety. Another option are the Alarm/Indicating type
fuses, but they are even more expensive. Expect to pay about $1/ea for the
fuse, and $2/ea for the sockets.

I think If I were going to build an electronically programmable demo ROM
of some sort, I'd use relays or transistors, each with a status indicating
LED. It would be easy to make a relay self-latching by using a set of
normally open contacts to keep the relay powered. A SCR could also work
well, since it would be self-latching as long as power was applied.

-Toth
Received on Wed Apr 10 2002 - 22:36:17 BST