On 04/24/2018 03:10 PM, D. Hugh Redelmeier via talk wrote:
First, lets think of a neon tube. It gets turned on when a high voltage is applied. With no voltage, no light. But once it has started, an intermediate voltage can maintain the light. If it hasn't started, that voltage will leave the tube off. So, powered by that voltage, the tube is a memory. You can tell its state by the amount of current it draws.
Neon lamps have long been known to have a memory effect. Many years ago, I worked on an ancient system, made by Teleregister, at the old Toronto Stock Exchange on Bay St.. It used neon bulbs for some storage. It also used a memory drum and flip flops built around 4 vacuum tubes. One of my first tasks in the morning was to slowly crank up the filament voltage, for all the vacuum tubes in the system. I also had to start a motor/generator set, to provide +/- 130V DC to run it. Go to the link and search on Teleregister for a description. http://www.torontoghosts.org/index.php/the-city-of-toronto/public-buildings/122-the-former-toronto-stock-exchange-current-design-exchange-?showall=1&limitstart= That system was installed over a year before I was born!