TTL homebrew CPUs

[Allison]

While interesting and at least classic and technical can you relate it to 
computers?

Allison



Tony Duell wrote:
>> I do remember the "miniature camera" 22.5v photoflash, but to my 
>> knowledge, the standard "press photographer" flash units that used 
>> large incandescent-lamp-sized bulbs all took D cells.
> 
> Most did, I think. In the UK, GEC (who AFAIK are noting to do with the 
> American GE company) sold special low-ionternal-resistance D-cells (we 
> called them 'U2' size at the time) for this appliocation
> 
> The problem with directly firing the flashbulb from the battery was that 
> as the battery aged its internal resistance increased. In the end the 
> bulb would fail to fire at all, but before, the lower current throug hthe 
> ignitor fillament meant the bulb took longer to fire, messing up the 
> synchonisation. Probably not a problem on the Speedgraphic/MPP Micropress 
> shutters (large format focal plane shutters that took a good 1/4s to go 
> across the film)
> 
> Leica sold a flashgun which took ES cap flashbulbs or SCC (single contact 
> small bayonet cap) with an adapter that was supplied with the unit.  The 
> original design used a special 6V dry batttery, this was quickly replaced 
> by a holder that took 4 AA cells in series. Then there was a 
> battery/capacitor module (22.5V battery) that fitted in place of that, 
> making contacct with the battery terminals and the metal case of the 
> flashgun (which was the connection between the bulb and sync contact). 
> 
> I've also got a SCC-cap flashgun that seems to have been designed for TLR 
> cameras (from the bracket that came with it). It either uses a pair of C 
> cells or a 22.5V baettery + a resisotr/capacitor module that was included 
> with the unit.
> 
> -tony
>