new hamfest finds

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Sat Jun 5 17:56:31 2004

> My dad had (probably still has, knowing him) a big camera flash unit that
> features one of these batteries. Big unit the size of a handbag with a
> shoulder strap, with the accumulator in this, and flash gun on the end of a
> spiral cord. I was always fascinated with it as a kid, so I guess that
> places it earlier than the '70s...

These sort of units were quite common at one time (and often used
lead-acid 'wet cell' accumulators). Actually, I'd not be suprised if the
batteries were still available somewhere..

Sometimes there were 2 or 3 plastic balls of different densities inside.
They floated or sank depending on the density of the eletrolyte, which in
turn depended on the state of charge of the cell. Interesting idea.

Getting the HT for the 'electronic flash' tube was something of an
entertainment before transistors (which took all the fun out of it, due
to the ease of making an oscillator that would run off a 6V battery).
Some manufacturers used a mechanical vibrator, like the one in a car
radio [1] to chop up the DC from a battery to feed it into a transformer.
Others used HV (250V or so) batteries. The Voigtlander Vitrona, one of
the first cameras to have built-in electronic flash, did this -- a
handle containing an HV battery plugged into the bottom of the cammera.

[1] I am showing my age. This was how they got the HT (B+) voltage for
valves (tubes) in car radios about 50 years ago...

-tony
Received on Sat Jun 05 2004 - 17:56:31 BST