charger105 wrote:Yeah, the extra row of dots make a big difference......they look awesome
Size was certainly a big issue for Hamilton. The Electrodata module had specially produced packages. The bottom digits for seconds are oriented sideways, and the hours digit is cut in half............all in an attempt to reduce overall size. Pretty sure I read on OldPulsars that Electrodata produced there own PCBs and sent them to HP for addition of the diodes and chip.
So with 5.5 of these in a watch it'd draw 550mA when displaying
?
Hamilton must've been very confident of rapid improvements to announce the watch with these displays. I think this was the module that kept running out of batteries on the Johnny Carson show.
Rgds.
I too have some 5082-7000's
They were initially produced in Feb 1969, and were the worlds first "Solid State Numeric Indicators". They used an array of individual but very inefficient LED emitters. Depending on brightness and number being displayed, they can consume up to 150ma !! That would be nearer 5ma these days.
I would have thought the original 1970 P1 prototypes had reduced brightness to preserve the batteries for their initial launch and the Carson show. And I'm not surprised the prototypes only lasted 20 minutes between battery swaps !
Also, bear in mind that the original ED circuit, and the final P1, all used multiplexed displays at 64hz (I think..) IE, only one digit is on at any one time, and its persistence of vision that makes them all look on at once. In other words the maximum current is still only going to be the most used by any one digit and not 500ma - that would kill the button cells in seconds, and probably get a tad hot.
Another interesting point about the 1970 P1 prototypes was that they didn't show hours+mins+seconds all at once. It was either 4 digits for Hours+mins, or 2 digits for seconds if the button was held down. If you look at the ultra rare P1 users manual that some owners still have, it shows two photos of the 1972 P1 using a 6 digit 25 chip E/D module with 4 digits on, and the 2nd photo shows just the seconds working in the
lower part of the display, below the hours/mins .. which of course vanished when the initial P1's were all recalled and the modules upgraded in late 1972 to use the P2 circuitry.